JEE Main & Advanced Physics Magnetic Effects of Current / करंट का चुंबकीय प्रभाव Question Bank

done Motion of Charged Particle In Magnetic Field Total Questions - 118

• question_answer1)
  A proton moving with a constant velocity passes through a region of space without any change in its velocity. If \[\overrightarrow{E}\] and \[\overrightarrow{B}\] represent the electric and magnetic fields respectively, then this region of space may have                    [IIT-JEE 1985; AMU 1995; AFMC 2001; Roorkee 2000; AMU (Med.) 2000]
  A)
             \[E=0,\,B=0\]                        done clear
  B)
             \[E=0,\,B\ne 0\] done clear
  C)
             \[E\ne 0,\,B=0\]                  done clear
  D)
             \[E\ne 0,\,B\ne 0\] done clear
  View Solution play_arrow

• question_answer2)
  A uniform electric field and a uniform magnetic field are produced, pointed in the same direction. An electron is projected with its velocity pointing in the same direction [NCERT 1980; CBSE PMT 1993; JIPMER 1997;  AIEEE 2005]
  A)
             The electron will turn to its right done clear
  B)
             The electron will turn to its left done clear
  C)
             The electron velocity will increase in magnitude done clear
  D)
             The electron velocity will decrease in magnitude done clear
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• question_answer3)
  Two particles X and Y having equal charges, after being accelerated through the same potential difference, enter a region of uniform magnetic field and describes circular path of radius \[{{R}_{1}}\] and \[{{R}_{2}}\] respectively. The ratio of mass of X to that of Y is [IIT-JEE 1988; CBSE PMT1995; MP PMT 2001]
  A)
             \[{{\left( \frac{{{R}_{1}}}{{{R}_{2}}} \right)}^{1/2}}\]             done clear
  B)
             \[\frac{{{R}_{2}}}{{{R}_{1}}}\] done clear
  C)
             \[{{\left( \frac{{{R}_{1}}}{{{R}_{2}}} \right)}^{2}}\]   done clear
  D)
             \[\frac{{{R}_{1}}}{{{R}_{2}}}\] done clear
  View Solution play_arrow

• question_answer4)
  A beam of ions with velocity \[2\times {{10}^{5}}\,m/s\] enters normally into a uniform magnetic field of \[4\times {{10}^{-2}}\,tesla\]. If the specific charge of the ion is \[5\times {{10}^{7}}\,C/kg\], then the radius of the circular path described will be                                         [NCERT 1983; BVP 2003]
  A)
             0.10 m                                      done clear
  B)
             0.16 m done clear
  C)
              0.20 m                                     done clear
  D)
             0.25 m done clear
  View Solution play_arrow

• question_answer5)
  The radius of curvature of the path of the charged particle in a uniform magnetic field is directly proportional to                                                               [MNR 1995; UPSEAT 1999, 2000]
  A)
             The charge on the particle done clear
  B)
             The momentum of the particle done clear
  C)
             The energy of the particle done clear
  D)
             The intensity of the field done clear
  View Solution play_arrow

• question_answer6)
  An electron has mass \[9\times {{10}^{-31}}\,kg\] and charge \[1.6\times {{10}^{-19}}C\] is moving with a velocity of \[{{10}^{6}}\,m/s\], enters a region where magnetic field exists. If it describes a circle of radius 0.10 m, the intensity of magnetic field must be [NCERT 1982; CPMT 1989; DCE 2005]
  A)
             \[1.8\times {{10}^{-4}}\,T\]    done clear
  B)
             \[5.6\times {{10}^{-5}}\,T\] done clear
  C)
             \[14.4\times {{10}^{-5}}\,T\]  done clear
  D)
             \[1.3\times {{10}^{-6}}\,T\] done clear
  View Solution play_arrow

• question_answer7)
  A proton (mass m and charge +e) and an \[\alpha -\]particle (mass 4m and charge +2e) are projected with the same kinetic energy at right angles to the uniform magnetic field. Which one of the following statements will be true                    [NCERT 1983]
  A)
             The \[\alpha -\]particle will be bent in a circular path with a small radius that for the proton done clear
  B)
             The radius of the path of the \[\alpha -\]particle will be greater than that of the proton done clear
  C)
             The \[\alpha -\]particle and the proton will be bent in a circular path with the same radius done clear
  D)
             The \[\alpha -\]particle and the proton will go through the field in a straight line done clear
  View Solution play_arrow

• question_answer8)
  A charged particle moving in a magnetic field experiences a resultant force                                          [MP PMT 1994]
  A)
             In the direction of field done clear
  B)
             In the direction opposite to that field done clear
  C)
             In the direction perpendicular to both the field and its velocity done clear
  D)
             None of the above done clear
  View Solution play_arrow

• question_answer9)
  If the direction of the initial velocity of the charged particle is perpendicular to the magnetic field, then the orbit will be or The path executed by a charged particle whose motion is perpendicular to magnetic field is [MP PMT 1993; CPMT 1996]
  A)
             A straight line                       done clear
  B)
             An ellipse done clear
  C)
             A circle                                     done clear
  D)
             A helix done clear
  View Solution play_arrow

• question_answer10)
  If the direction of the initial velocity of the charged particle is neither along nor perpendicular to that of the magnetic field, then the orbit will be                                     [MP PET 1993]
  A)
             A straight line                       done clear
  B)
             An ellipse done clear
  C)
             A circle                                     done clear
  D)
             A helix done clear
  View Solution play_arrow

• question_answer11)
  Particles having positive charges occasionally come with high velocity from the sky towards the earth. On account of the magnetic field of earth, they would be deflected towards the                                                            [NCERT 1977]
  A)
             North                                       done clear
  B)
             South done clear
  C)
             East                                           done clear
  D)
             West done clear
  View Solution play_arrow

• question_answer12)
  A 2 MeV proton is moving perpendicular to a uniform magnetic field of 2.5 tesla. The force on the proton is [CPMT 1989]
  A)
             \[2.5\times {{10}^{-10}}\,N\] done clear
  B)
             \[7.6\times {{10}^{-11}}\,N\] done clear
  C)
             \[2.5\times {{10}^{-11}}\,N\] done clear
  D)
             \[7.6\times {{10}^{-12}}\,N\] done clear
  View Solution play_arrow

• question_answer13)
  A charged particle moves with velocity v in a uniform magnetic field \[\overrightarrow{B}\]. The magnetic force experienced by the particle is                           [CBSE PMT 1990]
  A)
             Always zero done clear
  B)
             Never zero done clear
  C)
             Zero, if \[\overrightarrow{B}\] and \[\overrightarrow{v\,}\] are perpendicular done clear
  D)
             Zero, if \[\overrightarrow{B}\] and \[\overrightarrow{v\,}\] are parallel done clear
  View Solution play_arrow

• question_answer14)
  A proton is moving along Z-axis in a magnetic field. The magnetic field is along X-axis. The proton will experience a force along
  A)
             X-axis                                       done clear
  B)
             Y-axis done clear
  C)
             Z-axis                                       done clear
  D)
             Negative Z-axis done clear
  View Solution play_arrow

• question_answer15)
  A proton of mass m and charge +e is moving in a circular orbit in a magnetic field with energy 1 MeV. What should be the energy of \[\alpha -\]particle (mass = 4m and charge = + 2e), so that it can revolve in the path of same radius [BHU 1997]
  A)
             1 MeV                                      done clear
  B)
             4 MeV done clear
  C)
             2 MeV                                      done clear
  D)
             0.5 MeV done clear
  View Solution play_arrow

• question_answer16)
  An electron is moving with a speed of \[{{10}^{8}}\,m/\sec \] perpendicular to a uniform magnetic field of intensity B. Suddenly intensity of the magnetic field is reduced to B/2. The radius of the path becomes from the original value of r [MP PET 1993]
  A)
             No change                             done clear
  B)
             Reduces to r / 2 done clear
  C)
             Increases to 2r                     done clear
  D)
             Stops moving done clear
  View Solution play_arrow

• question_answer17)
  A proton and an \[\alpha -\]particle enter a uniform magnetic field perpendicularly with the same speed. If proton takes 25 \[\mu \] sec to make 5 revolutions, then the periodic time for the \[\alpha -\]particle would be                                                                             [MP PET 1993]
  A)
             50 \[\mu \] sec                     done clear
  B)
             25 \[\mu \] sec done clear
  C)
             10 \[\mu \] sec                     done clear
  D)
             5 \[\mu \] sec done clear
  View Solution play_arrow

• question_answer18)
  A proton (mass \[=1.67\times {{10}^{-27}}\,kg\] and charge \[=1.6\times {{10}^{-19}}\,C)\] enters perpendicular to a magnetic field of intensity 2 \[weber/{{m}^{2}}\] with a velocity \[3.4\times {{10}^{7}}\,m/\sec \]. The acceleration of the proton should be                   [DPMT 1999]
  A)
             \[6.5\times {{10}^{15}}\,m/{{\sec }^{2}}\]                   done clear
  B)
             \[6.5\times {{10}^{13}}\,m/{{\sec }^{2}}\] done clear
  C)
             \[6.5\times {{10}^{11}}\,m/{{\sec }^{2}}\]                   done clear
  D)
             \[6.5\times {{10}^{9}}\,m/{{\sec }^{2}}\] done clear
  View Solution play_arrow

• question_answer19)
  An \[\alpha -\]particle travels in a circular path of radius 0.45 m in a magnetic field \[B=1.2\,Wb/{{m}^{2}}\] with a speed of \[2.6\times {{10}^{7}}\,m/\sec \]. The period of revolution of the \[\alpha -\]particle is
  A)
             \[1.1\times {{10}^{-5}}\,\sec \]                                         done clear
  B)
             \[1.1\times {{10}^{-6}}\sec \] done clear
  C)
             \[1.1\times {{10}^{-7}}\,\sec \]                                         done clear
  D)
             \[1.1\times {{10}^{-8}}\,\sec \] done clear
  View Solution play_arrow

• question_answer20)
  A uniform magnetic field B is acting from south to north and is of magnitude 1.5 \[Wb/{{m}^{2}}\]. If a proton having mass \[=1.7\times {{10}^{-27}}\,kg\] and charge \[=1.6\times {{10}^{-19}}\,C\] moves in this field vertically downwards with energy 5 MeV, then the force acting on it will be                                     [Pb. PMT 2002]
  A)
             \[7.4\times {{10}^{12}}\,N\]  done clear
  B)
             \[7.4\times {{10}^{-12}}\,N\] done clear
  C)
             \[7.4\times {{10}^{19}}\,N\]  done clear
  D)
             \[7.4\times {{10}^{-19}}\,N\] done clear
  View Solution play_arrow

• question_answer21)
  A strong magnetic field is applied on a stationary electron, then                [BIT 1989; MP PMT 1995; CPMT 1999]
  A)
             The electron moves in the direction of the field done clear
  B)
             The electron moves in an opposite direction done clear
  C)
             The electron remains stationary done clear
  D)
             The electron starts spinning done clear
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• question_answer22)
  A uniform magnetic field acts at right angles to the direction of motion of electrons. As a result, the electron moves in a circular path of  radius 2 cm. If the speed of the electrons is doubled, then the radius of the circular path will be [CBSE PMT 1991]
  A)
             2.0 cm                                      done clear
  B)
             0.5 cm done clear
  C)
             4.0 cm                                      done clear
  D)
             1.0 cm done clear
  View Solution play_arrow

• question_answer23)
  A deutron of kinetic energy 50 keV is describing a circular orbit of radius 0.5 metre in a plane perpendicular to magnetic field \[\overrightarrow{B}\]. The kinetic energy of the proton that describes a circular orbit of radius 0.5 metre in the same plane with the same \[\overrightarrow{B}\] is                                        [CBSE PMT 1991]
  A)
             25 keV                                      done clear
  B)
             50 keV done clear
  C)
             200 keV                                   done clear
  D)
             100 keV done clear
  View Solution play_arrow

• question_answer24)
  If a proton is projected in a direction perpendicular to a uniform magnetic field with velocity v and an electron is projected along the lines of force, what will happen to proton and electron                                         [DPMT 1979]
  A)
             The electron will travel along a circle with constant speed and the proton will move along a straight line done clear
  B)
             Proton will move in a circle with constant speed and there will be no effect on the motion of electron done clear
  C)
             There will not be any effect on the motion of electron and proton done clear
  D)
             The electron and proton both will follow the path of a parabola done clear
  View Solution play_arrow

• question_answer25)
  An electron is travelling horizontally towards east. A magnetic field in vertically downward direction exerts a force on the electron along                                                     [EAMCET 1984]
  A)
             East                                           done clear
  B)
             West done clear
  C)
             North                                       done clear
  D)
             South done clear
  View Solution play_arrow

• question_answer26)
  Lorentz force can be calculated by using the formula [MP PET 1994, 2002, 03; CBSE PMT 2002]
  A)
             \[\overrightarrow{F}=q\,(\overrightarrow{E}+\overrightarrow{v}\times \overrightarrow{B})\]       done clear
  B)
             \[\overrightarrow{F}=q\,(\overrightarrow{E}-\overrightarrow{v}\times \overrightarrow{B})\] done clear
  C)
             \[\overrightarrow{F}=q\,(\overrightarrow{E}+\overrightarrow{v}\cdot \overrightarrow{B})\]         done clear
  D)
             \[\overrightarrow{F}=q\,(\overrightarrow{E}\times \overrightarrow{B}+\overrightarrow{v})\] done clear
  View Solution play_arrow

• question_answer27)
  A magnetic field                                   [MP PET 1994; Pb PMT 2003]
  A)
             Always exerts a force on a charged particle done clear
  B)
             Never exerts a force on a charged particle done clear
  C)
             Exerts a force, if the charged particle is moving across the magnetic field lines done clear
  D)
             Exerts a force, if the charged particle is moving along the magnetic field lines done clear
  View Solution play_arrow

• question_answer28)
  A proton enters a magnetic field of flux density \[1.5\,weber/{{m}^{2}}\] with a velocity of \[2\times {{10}^{7}}\,m/\sec \] at an angle of \[30{}^\circ \] with the field. The force on the proton will be [MP PET 1994 ; Pb. PMT 2004]
  A)
             \[2.4\times {{10}^{-12}}\,N\] done clear
  B)
             \[0.24\times {{10}^{-12}}\,N\] done clear
  C)
             \[24\times {{10}^{-12}}\,N\]  done clear
  D)
             \[0.024\times {{10}^{-12}}\,N\] done clear
  View Solution play_arrow

• question_answer29)
  If a particle of charge \[{{10}^{-12}}\,coulomb\] moving along the \[\hat{x}-\]direction with a velocity \[{{10}^{5}}\,m/s\] experiences a force of \[{{10}^{-10}}\,newton\] in \[\hat{y}-\]direction due to magnetic field, then the minimum magnetic field is         [MP PMT 1994]
  A)
             \[6.25\times {{10}^{3}}\,tesla\] in \[\hat{z}-\]direction done clear
  B)
             \[{{10}^{-15}}\,tesla\] in \[\hat{z}-\]direction done clear
  C)
             \[6.25\times {{10}^{-3}}\,tesla\] in \[\hat{z}-\]direction done clear
  D)
             \[{{10}^{-3}}\,tesla\] in \[\hat{z}-\]direction done clear
  View Solution play_arrow

• question_answer30)
  If a proton, deutron and \[\alpha -\]particle on being accelerated by the same potential difference enters perpendicular to the magnetic field, then the ratio of their kinetic energies is [MP PMT 2003; J & K CET 2005]
  A)
             1 : 2 : 2                                     done clear
  B)
             2 : 2 : 1 done clear
  C)
             1 : 2 : 1                                     done clear
  D)
             1 : 1 : 2 done clear
  View Solution play_arrow

• question_answer31)
  Which of the following statement is true [Manipal MEE 1995]
  A)
             The presence of a large magnetic flux through a coil maintains a current in the coil if the circuit is continuous done clear
  B)
             A coil of a metal wire kept stationary in a non-uniform magnetic field has an e.m.f. induced in it done clear
  C)
             A charged particle enters a region of uniform magnetic field at an angle of \[85{}^\circ \] to the magnetic lines of force; the path of the particle is a circle done clear
  D)
             There is no change in the energy of a charged particle moving in a magnetic field although a magnetic force is acting on it done clear
  View Solution play_arrow

• question_answer32)
  An electron and a proton enter region of uniform magnetic field in a direction at right angles to the field with the same kinetic energy. They describe circular paths of radius \[{{r}_{e}}\] and \[{{r}_{p}}\] respectively. Then                                        [Manipal MEE 1995]
  A)
             \[{{r}_{e}}={{r}_{p}}\] done clear
  B)
             \[{{r}_{e}}<{{r}_{p}}\] done clear
  C)
             \[{{r}_{e}}>{{r}_{p}}\] done clear
  D)
             \[{{r}_{e}}\] may be less than or greater than \[{{r}_{p}}\] depending on the direction of the magnetic field done clear
  View Solution play_arrow

• question_answer33)
  A proton of mass \[1.67\times {{10}^{-27}}kg\] and charge \[1.6\times {{10}^{-19}}\,C\] is projected with a speed of \[2\times {{10}^{6}}\,m/s\] at an angle of \[60{}^\circ \] to the \[X-\]axis. If a uniform magnetic field of 0.104 Tesla is applied along \[Y-\]axis, the path of proton is  [IIT-JEE 1995]
  A)
             A circle of radius = 0.2 m and time period \[\pi \times {{10}^{-7}}s\] done clear
  B)
             A circle of radius = 0.1 m and time period \[2\pi \times {{10}^{-7}}s\] done clear
  C)
             A helix of radius = 0.1 m and time period \[2\pi \times {{10}^{-7}}s\] done clear
  D)
             A helix of radius = 0.2 m and time period \[4\pi \times {{10}^{-7}}s\] done clear
  View Solution play_arrow

• question_answer34)
  A proton and a deutron both having the same kinetic energy, enter perpendicularly into a uniform magnetic field B. For motion of proton and deutron on circular path of radius \[{{R}_{p}}\] and \[{{R}_{d}}\] respectively, the correct statement is [MP PET 1995]
  A)
             \[{{R}_{d}}=\sqrt{2}\,{{R}_{p}}\]                                      done clear
  B)
             \[{{R}_{d}}={{R}_{p}}/\sqrt{2}\] done clear
  C)
             \[{{R}_{d}}={{R}_{p}}\]     done clear
  D)
             \[{{R}_{d}}=2{{R}_{p}}\] done clear
  View Solution play_arrow

• question_answer35)
  A proton (or charged particle) moving with velocity v is acted upon by electric field E and magnetic field B. The proton will move undeflected if [MP PMT 1995, 2003; UPSEAT 2002; DPMT 2003]
  A)
             E is perpendicular to B done clear
  B)
             E is parallel to v and perpendicular to B done clear
  C)
             E, B and v are mutually perpendicular and \[v=\frac{E}{B}\] done clear
  D)
             E and B both are parallel to v done clear
  View Solution play_arrow

• question_answer36)
  A proton and an electron both moving with the same velocity v enter into a region of magnetic field directed perpendicular to the velocity of the particles. They will now move in circular orbits such that                       [MP PMT 1995]
  A)
             Their time periods will be same done clear
  B)
             The time period for proton will be higher done clear
  C)
             The time period for electron will be higher done clear
  D)
             Their orbital radii will be same done clear
  View Solution play_arrow

• question_answer37)
  A charge + Q is moving upwards vertically. It enters a magnetic field directed to the north. The force on the charge will be towards                                    [MP PMT 1995; AMU (Engg.) 2000]
  A)
             North                                       done clear
  B)
             South done clear
  C)
             East                                           done clear
  D)
             West done clear
  View Solution play_arrow

• question_answer38)
  An electron is moving on a circular path of radius r with speed v in a transverse magnetic field B. e/m for it will be [MP PMT 2003]
  A)
             \[\frac{v}{Br}\]                     done clear
  B)
             \[\frac{B}{rv}\] done clear
  C)
             Bvr done clear
  D)
             \[\frac{vr}{B}\] done clear
  View Solution play_arrow

• question_answer39)
  A beam of well collimated cathode rays travelling with a speed of \[5\times {{10}^{6}}\,m{{s}^{-1}}\] enter a region of mutually perpendicular electric and magnetic fields and emerge undeviated from this region. If \[|B|\,=0.02\,T\], the magnitude of the electric field is                                                               [Haryana CEE 1996]
  A)
             \[{{10}^{5}}\,V{{m}^{-1}}\]     done clear
  B)
             \[2.5\times {{10}^{8}}\,V{{m}^{-1}}\] done clear
  C)
             \[1.25\times {{10}^{10}}\,V{{m}^{-1}}\]                        done clear
  D)
             \[2\times {{10}^{3}}\,V{{m}^{-1}}\] done clear
  View Solution play_arrow

• question_answer40)
  An electron having charge \[1.6\times {{10}^{-19}}\,C\] and mass \[9\times {{10}^{-31}}\,kg\] is moving with \[4\times {{10}^{6}}\,m{{s}^{-1}}\] speed in a magnetic field \[2\times {{10}^{-1}}\,tesla\] in a circular orbit. The force acting on electron and the radius of the circular orbit will be [MP PET 1996; JIPMER 2000; BVP 2003]
  A)
             \[12.8\times {{10}^{-13}}N,\,1.1\times {{10}^{-4}}m\] done clear
  B)
             \[1.28\times {{10}^{-14}}N,\,1.1\times {{10}^{-3}}m\] done clear
  C)
             \[1.28\times {{10}^{-13}}N,\,1.1\times {{10}^{-3}}m\] done clear
  D)
             \[1.28\times {{10}^{-13}}N,\,1.1\times {{10}^{-4}}m\] done clear
  View Solution play_arrow

• question_answer41)
  An electron enters a magnetic field whose direction is perpendicular to the velocity of the electron. Then [MP PMT 1996; CBSE PMT 2003]
  A)
             The speed of the electron will increase done clear
  B)
             The speed of the electron will decrease done clear
  C)
             The speed of the electron will remain the same done clear
  D)
             The velocity of the electron will remain the same done clear
  View Solution play_arrow

• question_answer42)
  An electron is moving in the north direction. It experiences a force in vertically upward direction. The magnetic field at the position of the electron is in the direction of  [MP PET 2003]
  A)
             East                                           done clear
  B)
             West done clear
  C)
             North                                       done clear
  D)
             South done clear
  View Solution play_arrow

• question_answer43)
  A current carrying long solenoid is placed on the ground with its axis vertical. A proton is falling along the axis of the solenoid with a velocity v. When the proton enters into the solenoid, it will
  A)
             Be deflected from its path done clear
  B)
             Be accelerated along the same path done clear
  C)
             Be decelerated along the same path done clear
  D)
             Move along the same path with no change in velocity done clear
  View Solution play_arrow

• question_answer44)
  A charged particle of mass m and charge q describes circular motion of radius r in a uniform magnetic field of strength B. The frequency of revolution is      [MP PET 1997; RPET 2001]
  A)
             \[\frac{Bq}{2\pi m}\]         done clear
  B)
             \[\frac{Bq}{2\pi rm}\] done clear
  C)
             \[\frac{2\pi m}{Bq}\]         done clear
  D)
             \[\frac{Bm}{2\pi q}\] done clear
  View Solution play_arrow

• question_answer45)
  An electron is accelerated by a potential difference of 12000 volts. It then enters a uniform magnetic field of \[{{10}^{-3}}\,T\] applied perpendicular to the path of electron. Find the radius of path. Given mass of electron \[=9\times {{10}^{-31}}\,kg\] and charge on electron \[=1.6\times {{10}^{-19}}\,C\]                               [MP PET 1997]
  A)
             36.7 m                                      done clear
  B)
             36.7 cm done clear
  C)
             3.67 m                                      done clear
  D)
             3.67 cm done clear
  View Solution play_arrow

• question_answer46)
  -The charge on a particle Y is double the charge on particle X. These two particles X and Y after being accelerated through the same potential difference enter a region of uniform magnetic field and describe circular paths of radii \[{{R}_{1}}\] and \[{{R}_{2}}\] respectively. The ratio of the mass of X to that of Y is                                         [MP PET 1997]
  A)
             \[{{\left( \frac{2{{R}_{1}}}{{{R}_{2}}} \right)}^{2}}\] done clear
  B)
             \[{{\left( \frac{{{R}_{1}}}{2{{R}_{2}}} \right)}^{2}}\] done clear
  C)
    \[\frac{R_{1}^{2}}{2R_{2}^{2}}\]   done clear
  D)
             \[\frac{2{{R}_{1}}}{{{R}_{2}}}\] done clear
  View Solution play_arrow

• question_answer47)
  A particle with \[{{10}^{-11}}\,coulomb\] of charge and \[{{10}^{-7}}\,kg\] mass is moving with a velocity of \[{{10}^{8}}\,m/s\] along the y-axis. A uniform static magnetic field \[B=0.5\,Tesla\] is acting along the x-direction. The force on the particle is                 [MP PMT 1997]
  A)
             \[5\times {{10}^{-11}}\,N\] along \[\hat{i}\]               done clear
  B)
             \[5\times {{10}^{3}}\] N along \[\hat{k}\] done clear
  C)
             \[5\times {{10}^{-11}}\,N\] along \[-\hat{j}\]             done clear
  D)
             \[5\times {{10}^{-4}}\,N\] along \[-\hat{k}\] done clear
  View Solution play_arrow

• question_answer48)
  A particle of charge q and mass m moving with a velocity v along the x-axis enters the region x > 0 with uniform magnetic field B along the \[\hat{k}\] direction. The particle will penetrate in this region in the x-direction upto a distance d equal to                                                   [MP PMT 1997]
  A)
             Zero                                          done clear
  B)
             \[\frac{mv}{qB}\] done clear
  C)
             \[\frac{2mv}{qB}\]             done clear
  D)
             Infinity done clear
  View Solution play_arrow

• question_answer49)
  A charged particle is moving with velocity v in a magnetic field of induction B. The force on the particle will be maximum when                                                          [MP PMT/PET 1998]
  A)
             v and B are in the same direction done clear
  B)
             v and B are in opposite directions done clear
  C)
             v and B are perpendicular done clear
  D)
             v and B are at an angle of \[45{}^\circ \] done clear
  View Solution play_arrow

• question_answer50)
  A charged particle enters a magnetic field H with its initial velocity making an angle of \[45{}^\circ \] with H. The path of the particle will be          [MP PET 1999; AIIMS 1999; BHU 1999]
  A)
             A straight line                       done clear
  B)
             A circle done clear
  C)
             An ellipse                               done clear
  D)
             A helix done clear
  View Solution play_arrow

• question_answer51)
  An electron and a proton enter a magnetic field perpendicularly. Both have same kinetic energy. Which of the following is true                                                         [MP PET 1999]
  A)
             Trajectory of electron is less curved done clear
  B)
             Trajectory of proton is less curved done clear
  C)
             Both trajectories are equally curved done clear
  D)
             Both move on straight-line path done clear
  View Solution play_arrow

• question_answer52)
  A charged particle moves in a uniform magnetic field. The velocity of the particle at some instant makes an acute angle with the magnetic field. The path of the particle will be [MP PMT 1999]
  A)
             A straight line done clear
  B)
             A circle done clear
  C)
             A helix with uniform pitch done clear
  D)
             A helix with non-uniform pitch done clear
  View Solution play_arrow

• question_answer53)
  An electron is moving along positive x-axis. To get it moving on an anticlockwise circular path in x-y plane, a magnetic filed is applied                                                            [MP PMT 1999]
  A)
             Along positive y-axis          done clear
  B)
             Along positive z-axis done clear
  C)
             Along negative y-axis        done clear
  D)
             Along negative z-axis done clear
  View Solution play_arrow

• question_answer54)
  A moving charge will gain energy due to the application of           [CPMT 1999]
  A)
             Electric field                           done clear
  B)
             Magnetic field done clear
  C)
             Both of these                       done clear
  D)
             None of these done clear
  View Solution play_arrow

• question_answer55)
  A proton, a deuteron and an \[\alpha -\]particle having the same kinetic energy are moving in circular trajectories in a constant magnetic field. If \[{{r}_{p}},\,{{r}_{d}}\] and \[{{r}_{\alpha }}\] denote respectively the radii of the trajectories of these particles, then [IIT 1997 Re-Exam]
  A)
             \[{{r}_{\alpha }}={{r}_{p}}<{{r}_{d}}\]                            done clear
  B)
             \[{{r}_{\alpha }}>{{r}_{d}}>{{r}_{p}}\] done clear
  C)
             \[{{r}_{\alpha }}={{r}_{d}}>{{r}_{p}}\]                            done clear
  D)
             \[{{r}_{p}}={{r}_{d}}={{r}_{\alpha }}\] done clear
  View Solution play_arrow

• question_answer56)
  When a magnetic field is applied in a direction perpendicular to the direction of cathode rays, then their [EAMCET 1994; BHU 2005]
  A)
             Energy decreases done clear
  B)
             Energy increases done clear
  C)
             Momentum increases done clear
  D)
             Momentum and energy remain unchanged done clear
  View Solution play_arrow

• question_answer57)
  A charge moves in a circle perpendicular to a magnetic field. The time period of revolution is independent of [RPET 1997; AIEEE 2002]
  A)
             Magnetic field                      done clear
  B)
             Charge done clear
  C)
             Mass of the particle           done clear
  D)
             Velocity of the particle done clear
  View Solution play_arrow

• question_answer58)
  A proton of energy 200 MeV enters the magnetic field of 5 T. If direction of field is from south to north and motion is upward, the force acting on it will be                     [RPET 1997]
  A)
             Zero                                          done clear
  B)
             \[1.6\times {{10}^{-10}}N\] done clear
  C)
             \[3.2\times {{10}^{-8}}N\]      done clear
  D)
             \[1.6\times {{10}^{-6}}N\] done clear
  View Solution play_arrow

• question_answer59)
  An electron enters a region where magnetic  and electric (E) fields are mutually perpendicular to one another, then [CBSE PMT1993]
  A)
             It will always move in the direction of B done clear
  B)
             It will always move in the direction of E done clear
  C)
             It always possess circular motion done clear
  D)
             It can go undeflected also done clear
  View Solution play_arrow

• question_answer60)
  A charge moving with velocity v in X-direction is subjected to a field of magnetic induction in the negative X-direction. As a result, the charge will                                   [CBSE PMT1993]
  A)
             Remain unaffected done clear
  B)
             Start moving in a circular path Y-Z plane done clear
  C)
             Retard along X-axis done clear
  D)
             Move along a helical path around X-axis done clear
  View Solution play_arrow

• question_answer61)
  An electron and a proton with equal momentum enter perpendicularly into a uniform magnetic field, then                    [BHU 1997; AIEEE 2002; MH CET (Med.) 2000]
  A)
             The path of proton shall be more curved than that of electron done clear
  B)
             The path of proton shall be less curved than that of electron done clear
  C)
             Both are equally curved done clear
  D)
             Path of both will be straight line done clear
  View Solution play_arrow

• question_answer62)
  A positively charged particle moving due east enters a region of uniform magnetic field directed vertically upwards. The particle will                                                        [CBSE PMT 1997]
  A)
             Get deflected vertically upwards done clear
  B)
             Move in a circular orbit with its speed increased done clear
  C)
             Move in a circular orbit with its speed unchanged done clear
  D)
             Continue to move due east done clear
  View Solution play_arrow

• question_answer63)
  A particle moving in a magnetic field increases its velocity, then its radius of the circle                     [BHU 1998]
  A)
             Decreases                              done clear
  B)
             Increases done clear
  C)
             Remains the same              done clear
  D)
             Becomes half done clear
  View Solution play_arrow

• question_answer64)
  A particle is moving in a uniform magnetic field, then [BHU 1998]
  A)
             Its momentum changes but total energy remains the same done clear
  B)
             Both momentum and total energy remain the same done clear
  C)
             Both will change done clear
  D)
             Total energy changes but momentum remains the same done clear
  View Solution play_arrow

• question_answer65)
  If an electron is going in the direction of magnetic field \[\overrightarrow{B}\] with the velocity of \[\overrightarrow{v\,}\] then the force on electron is [RPMT 1999]
  A)
             Zero                                          done clear
  B)
             \[e\,(\overrightarrow{v\,}\cdot \overrightarrow{B})\] done clear
  C)
             \[e\,(\overrightarrow{v\,}\times \overrightarrow{B})\]     done clear
  D)
             None of these done clear
  View Solution play_arrow

• question_answer66)
  One proton beam enters a magnetic field of \[{{10}^{-4}}\]T normally, Specific charge = \[{{10}^{11}}\,C/kg.\] velocity = \[{{10}^{7}}\,m/s\]. What is the radius of the circle described by it        [DCE 1999]
  A)
             0.1 m                                        done clear
  B)
             1 m done clear
  C)
             10 m                                         done clear
  D)
             None of these done clear
  View Solution play_arrow

• question_answer67)
  In a cyclotron, the angular frequency of a charged particle is independent of                                       [CPMT 1999]
  A)
              Mass                                        done clear
  B)
              Speed done clear
  C)
              Charge                                    done clear
  D)
              Magnetic field done clear
  View Solution play_arrow

• question_answer68)
  A charged particle is moving in a uniform magnetic field in a circular path. Radius of circular path is R. When energy of particle is doubled, then new radius will be [CPMT 1999; Pb. PET 2002]
  A)
             \[R\sqrt{2}\]                         done clear
  B)
             \[R\sqrt{3}\] done clear
  C)
             2 R done clear
  D)
             3 R done clear
  View Solution play_arrow

• question_answer69)
  The radius of curvature of the path of a charged particle moving in a static uniform magnetic field is [Roorkee 1999]
  A)
             Directly proportional to the magnitude of the charge on the particle done clear
  B)
             Directly proportional to the magnitude of the linear momentum of the particle done clear
  C)
             Directly proportional to the kinetic energy of the particle   done clear
  D)
             Inversely proportional to the magnitude of the magnetic field done clear
  View Solution play_arrow

• question_answer70)
  A proton moving with a velocity, \[2.5\times {{10}^{7}}m/s\], enters a magnetic field of intensity 2.5T making an angle \[{{30}^{o}}\] with the magnetic field. The force on the proton is              [AFMC 2000; CBSE PMT 2000]
  A)
             \[3\times {{10}^{-12}}N\]        done clear
  B)
             \[5\times {{10}^{-12}}N\] done clear
  C)
             \[6\times {{10}^{-12}}\]N        done clear
  D)
             \[9\times {{10}^{-12}}N\] done clear
  View Solution play_arrow

• question_answer71)
  Maximum kinetic energy of the positive ion in the cyclotron is                                                    [Pb. PMT 2000]
  A)
             \[\frac{{{q}^{2}}B{{r}_{0}}}{2m}\]                                    done clear
  B)
             \[\frac{q{{B}^{2}}{{r}_{o}}}{2m}\] done clear
  C)
             \[\frac{{{q}^{2}}{{B}^{2}}r_{0}^{2}}{2m}\]                   done clear
  D)
             \[\frac{qB{{r}_{0}}}{2{{m}^{2}}}\] done clear
  View Solution play_arrow

• question_answer72)
  A charge q is moving in a magnetic field then the magnetic force does not depend upon                               [RPET 2000]
  A)
             Charge                                     done clear
  B)
             Mass done clear
  C)
             Velocity                                   done clear
  D)
             Magnetic field done clear
  View Solution play_arrow

• question_answer73)
  An electron is travelling in east direction and a magnetic field is applied in upward direction then electron will deflect in                                                                                           [RPET 2000]
  A)
             South                                       done clear
  B)
             North done clear
  C)
             West                                        done clear
  D)
             East done clear
  View Solution play_arrow

• question_answer74)
  A charge of 1C is moving in a magnetic field of 0.5Tesla with a velocity of 10m/sec Perpendicular to the field. Force experienced is                                                                [RPMT 2000]
  A)
             5 N done clear
  B)
             10 N done clear
  C)
             0.5 N                                         done clear
  D)
             0 N done clear
  View Solution play_arrow

• question_answer75)
  An electron of mass m and charge q is travelling with a speed v along a circular path of radius r at right angles to a uniform of magnetic field B. If speed of the electron is doubled and the magnetic field is halved, then resulting path would have a radius of    [Kerala PMT 2004; KCET 2000, 05]
  A)
             \[\frac{r}{4}\]                       done clear
  B)
             \[\frac{r}{2}\] done clear
  C)
             \[2r\]                                        done clear
  D)
             \[4r\] done clear
  View Solution play_arrow

• question_answer76)
  If an electron enters a magnetic field with its velocity pointing in the same direction as the magnetic field, then [MP PMT 2000]
  A)
             The electron will turn to its right done clear
  B)
             The electron will turn to its left done clear
  C)
             The velocity of the electron will increase done clear
  D)
             The velocity of the electron will remain unchanged done clear
  View Solution play_arrow

• question_answer77)
  A particle of mass m and charge q enters a magnetic field B perpendicularly with a velocity v, The radius of the circular path described by it will be                                   [MP PMT 2000]
  A)
             \[Bq/mv\]                              done clear
  B)
             \[mq/Bv\] done clear
  C)
             \[mB/qv\]                              done clear
  D)
             \[mv/Bq\] done clear
  View Solution play_arrow

• question_answer78)
  An electron moving towards the east enters a magnetic field directed towards the north. The force on the electron will be directed                                                            [MP PET 2000]
  A)
             Vertically upward                done clear
  B)
             Vertically downward done clear
  C)
             Towards the west               done clear
  D)
             Towards the south done clear
  View Solution play_arrow

• question_answer79)
  An electron (mass = 9.0×\[{{10}^{-31}}\]kg and charge =\[1.6\times {{10}^{-19}}\]coulomb) is moving in a circular orbit in a magnetic field of \[1.0\times {{10}^{-4}}\,weber/{{m}^{2}}.\] Its period of revolution is                         [MP PET 2000; Pb PET 2003]
  A)
              \[3.5\times {{10}^{-7}}\]sec  done clear
  B)
             \[7.0\times {{10}^{-7}}\]sec done clear
  C)
             \[1.05\times {{10}^{-6}}\]sec done clear
  D)
             \[2.1\times {{10}^{-6}}\]sec done clear
  View Solution play_arrow

• question_answer80)
  An electron (charge q coulomb) enters a magnetic field of H \[weber/{{m}^{2}}\] with a velocity of \[v\,m/s\] in the same direction as that of the field the force on the electron is    [MP PET 2000]
  A)
             Hqv Newton?s in the direction of the magnetic field  done clear
  B)
             Hqv dynes in the direction of the magnetic field done clear
  C)
             Hqv Newton?s at right angles to the direction of the magnetic field done clear
  D)
             Zero done clear
  View Solution play_arrow

• question_answer81)
  A homogeneous electric field E and a uniform magnetic field \[\overset{\to }{\mathop{B}}\,\] are pointing in the same direction. A proton is projected with its velocity parallel to \[\overset{\to }{\mathop{E}}\,\]. It will           [Roorkee 2000]
  A)
             Go on moving in the same direction with increasing velocity done clear
  B)
             Go on moving in the same direction with constant velocity done clear
  C)
             Turn to its right done clear
  D)
             Turn to its left done clear
  View Solution play_arrow

• question_answer82)
  The radius of circular path of an electron when subjected to a perpendicular magnetic field is [Pb. PMT 1999; DCE 2000; MH CET (Med.) 2000]
  A)
             \[\frac{mv}{Be}\]                done clear
  B)
             \[\frac{me}{Be}\] done clear
  C)
             \[\frac{mE}{Be}\]                done clear
  D)
             \[\frac{Be}{mv}\] done clear
  View Solution play_arrow

• question_answer83)
  Cyclotron is used to accelerate           [AIIMS 2001; BCECE 2004]
  A)
             Electrons                                done clear
  B)
             Neutrons done clear
  C)
             Positive ions                          done clear
  D)
             Negative ions done clear
  View Solution play_arrow

• question_answer84)
  Two particles A and B of masses \[{{m}_{A}}\] and \[{{m}_{B}}\] respectively and having the same charge are moving in a plane. A uniform magnetic field exists perpendicular to this plane. The speeds of the particles are \[{{v}_{A}}\] and \[{{v}_{B}}\] respectively, and the trajectories are as shown in the figure. Then   [IIT-JEE (Screening) 2001]
  A)
             \[{{m}_{A}}{{v}_{A}}<{{m}_{B}}{{v}_{B}}\] done clear
  B)
             \[{{m}_{A}}{{v}_{A}}>{{m}_{B}}{{v}_{B}}\] done clear
  C)
             \[{{m}_{A}}<{{m}_{B}}\,\,\text{and}\,\,{{v}_{A}}<{{v}_{B}}\] done clear
  D)
             \[{{m}_{A}}=\,{{m}_{B}}\,\text{and }{{v}_{A}}={{v}_{B}}\] done clear
  View Solution play_arrow

• question_answer85)
  A proton and an alpha particle are separately projected in a region where a uniform magnetic field exists. Their initial velocities are perpendicular to direction of magnetic field. If both the particles move around magnetic field in circles of equal radii, the ratio of momentum of proton to alpha particle \[\left( \frac{{{P}_{p}}}{{{P}_{\alpha }}} \right)\]is                                                                       [MP PET 2001]
  A)
             1     done clear
  B)
             \[\frac{1}{2}\] done clear
  C)
             2     done clear
  D)
             \[\frac{1}{4}\] done clear
  View Solution play_arrow

• question_answer86)
  A particle of mass 0.6 g and having charge of 25 nC is moving horizontally with a uniform velocity \[\text{1}\text{.2}\times \text{1}{{\text{0}}^{\text{4}}}m{{s}^{-1}}\] in a uniform magnetic field, then the value of the magnetic induction is \[(g=10\,m{{s}^{-2}})\]                                                      [EAMCET 2001]
  A)
             Zero                                          done clear
  B)
             10 T done clear
  C)
             20 T                                           done clear
  D)
             200 T done clear
  View Solution play_arrow

• question_answer87)
  An \[\alpha \] particle and a proton travel with same velocity in a magnetic field perpendicular to the direction of their velocities, find the ratio of the radii of their circular path [AIIMS 2004; DCE 2001, 03; Kerala PMT 2005]
  A)
             4 : 1                                           done clear
  B)
             1 : 4 done clear
  C)
             2 : 1                                           done clear
  D)
             1 : 2 done clear
  View Solution play_arrow

• question_answer88)
  Motion of a moving electron is not affected by  [AMU (Engg.) 2001]
  A)
             An electric field applied in the direction of motion done clear
  B)
             Magnetic field applied in the direction of motion done clear
  C)
             Electric field applied perpendicular to the direction of motion          done clear
  D)
             Magnetic field applied perpendicular to the direction of motion done clear
  View Solution play_arrow

• question_answer89)
  When a charged particle enters a uniform magnetic field its kinetic energy           [MP PMT 2001; MP PET 2002]
  A)
             Remains constant               done clear
  B)
             Increases done clear
  C)
             Decreases                              done clear
  D)
             Becomes zero done clear
  View Solution play_arrow

• question_answer90)
  If cathode rays are projected at right angles to a magnetic field, their trajectory is                                             [JIPMER 2002]
  A)
             Ellipse                                      done clear
  B)
             Circle done clear
  C)
             Parabola                                 done clear
  D)
             None of these done clear
  View Solution play_arrow

• question_answer91)
  At a specific instant emission of radioactive compound is deflected in a magnetic field. The compound can emit (i)       Electrons                                (ii)  Protons (iii)     \[H{{e}^{2+}}\]                    (iv) Neutrons The emission at the instant can be                                                           [AIEEE 2002]
  A)
             i, ii, iii                                        done clear
  B)
             i, ii, iii, iv done clear
  C)
             iv    done clear
  D)
             ii, iii done clear
  View Solution play_arrow

• question_answer92)
  Which particles will have minimum frequency of revolution when projected with the same velocity perpendicular to a magnetic field                                                        [Orissa JEE 2002]
  A)
             Li+   done clear
  B)
             Electron done clear
  C)
             Proton                                     done clear
  D)
             \[H{{e}^{+}}\] done clear
  View Solution play_arrow

• question_answer93)
  Mixed \[H{{e}^{+}}\] and \[{{O}^{2+}}\]ions (mass of \[H{{e}^{+}}=4\,\,amu\] and that of \[{{O}^{2+}}=16\,\,amu)\] beam passes a region of constant perpendicular magnetic field. If kinetic energy of all the ions is same then                                                                      [Orissa JEE 2002]
  A)
             \[H{{e}^{+}}\] ions will be deflected more than those of \[{{O}^{2+}}\] done clear
  B)
             \[H{{e}^{+}}\]ions will be deflected less than those of \[{{O}^{2+}}\] done clear
  C)
             All the ions will be deflected equally done clear
  D)
             No ions will be deflected done clear
  View Solution play_arrow

• question_answer94)
  An electron (mass = 9´ 10?31kg. Charge = 1.6 ´ 10?19C) whose kinetic energy is 7.2 ´ 10?18 joule is moving in a circular orbit in a magnetic field of 9 ´ 10?5 weber/m2. The radius of the orbit is                                                   [MP PMT 2002]
  A)
             1.25 cm                                    done clear
  B)
             2.5 cm done clear
  C)
             12.5 cm                                    done clear
  D)
             25.0 cm done clear
  View Solution play_arrow

• question_answer95)
  An electron enters a region where electrostatic field is 20N/C and magnetic field is 5T. If electron passes undeflected through the region, then velocity of electron will be  [DPMT 2002]
  A)
             \[0.25m{{s}^{-1}}\]             done clear
  B)
             \[2m{{s}^{-1}}\] done clear
  C)
             \[4m{{s}^{-1}}\]                   done clear
  D)
             \[8m{{s}^{-1}}\] done clear
  View Solution play_arrow

• question_answer96)
  A charged particle is released from rest in a region of steady uniform electric and magnetic fields which are parallel to each other the particle will move in a   [IIT-JEE 1999; DPMT 2000; UPSEAT 2003]
  A)
             Straight line                           done clear
  B)
             Circle done clear
  C)
             Helix                                         done clear
  D)
             Cycloid done clear
  View Solution play_arrow

• question_answer97)
  A particle of mass M and charge Q moving with velocity \[\overset{\to }{\mathop{v}}\,\]describes a circular path of radius R when subjected to a uniform transverse magnetic field of induction B. The work done by the field when the particle completes one full circle is                                                                                           [AIEEE 2003]
  A)
             \[B\,Qv\,2\pi \,R\]              done clear
  B)
             \[\left( \frac{M{{v}^{2}}}{R} \right)\,2\pi R\] done clear
  C)
             Zero                                          done clear
  D)
             \[BQ2\pi R\] done clear
  View Solution play_arrow

• question_answer98)
  A particle of charge \[-16\times {{10}^{-18}}\]coulomb moving with velocity \[10\,\,m{{s}^{-1}}\] along the x-axis enters a region where a magnetic field of induction B is along the y-axis, and an electric field of magnitude \[{{10}^{4}}\,\,V/m\]is along the negative    z-axis. If the charged particle continues moving along the   x-axis, the magnitude of B is                                                           [AIEEE 2003]
  A)
             \[{{10}^{-3}}Wb/{{m}^{2}}\] done clear
  B)
             \[{{10}^{3}}Wb/{{m}^{2}}\] done clear
  C)
             \[{{10}^{5}}Wb/{{m}^{2}}\]    done clear
  D)
             \[{{10}^{16}}Wb/{{m}^{2}}\] done clear
  View Solution play_arrow

• question_answer99)
  Two ions having masses in the ratio 1 : 1 and charges 1 : 2 are projected into uniform magnetic field perpendicular to the field with speeds in the ratio 2 : 3. The ratio of the radii of circular paths along which the two particles move is [EAMCET 2003]
  A)
             4 : 3                                           done clear
  B)
             2 : 3 done clear
  C)
             3 : 1                                           done clear
  D)
             1 : 4 done clear
  View Solution play_arrow

• question_answer100)
  An electron is travelling along the x-direction. It encounters a magnetic field in the y-direction. Its subsequent motion will be                                                                                [AIIMS 2003]
  A)
             Straight line along the x-direction done clear
  B)
             A circle in the xz-plane done clear
  C)
             A circle in the yz-plane done clear
  D)
             A circle in the xy-plane done clear
  View Solution play_arrow

• question_answer101)
  An electron and a proton have equal kinetic energies. They enter in a magnetic field perpendicularly, Then [UPSEAT 2003]
  A)
             Both will follow a circular path with same radius done clear
  B)
             Both will follow a helical path done clear
  C)
             Both will follow a parabolic path                                       done clear
  D)
             All the statements are false done clear
  View Solution play_arrow

• question_answer102)
  Electrons move at right angles to a magnetic field of \[1.5\times {{10}^{-2}}\]Tesla with a speed of \[6\times {{10}^{7}}m/s.\]If the specific charge of the electron is \[1.7\times {{10}^{11}}\]C/kg. The radius of the circular path will be                                                         [BHU 2003]
  A)
             2.9 cm                                      done clear
  B)
             3.9 cm done clear
  C)
             2.35 cm                                    done clear
  D)
             3 cm done clear
  View Solution play_arrow

• question_answer103)
  The cyclotron frequency of an electron grating in a magnetic field of 1 T is approximately                              [AIIMS 2004]
  A)
             28 MHz                                    done clear
  B)
             280 MHz done clear
  C)
             2.8 GHz                                    done clear
  D)
             28 GHz done clear
  View Solution play_arrow

• question_answer104)
  In the given figure, the electron enters into the magnetic field. It deflects in ...... direction                           [Orissa PMT 2004]
  A)
             + ve X direction  done clear
  B)
             ? ve X direction done clear
  C)
             + ve Y direction done clear
  D)
             ? ve Y direction done clear
  View Solution play_arrow

• question_answer105)
  A proton of energy 8 eV is moving in a circular path in a uniform magnetic field. The energy of an alpha particle moving in the same magnetic field and along the same path will be                                          [J & K CET 2004]
  A)
             4 eV                                          done clear
  B)
             2 eV done clear
  C)
             8 eV                                          done clear
  D)
             6 eV done clear
  View Solution play_arrow

• question_answer106)
  An electron, a proton, a deuteron and an alpha particle, each having the same speed are in a region of constant magnetic field perpendicular to the direction of the velocities of the particles. The radius of the circular orbits of these particles are respectively Re, Rp, Rd and Ra. It follows that                                                              [UPSEAT 2004]
  A)
             \[{{R}_{e}}={{R}_{p}}\]     done clear
  B)
             \[{{R}_{p}}={{R}_{d}}\] done clear
  C)
             \[{{R}_{d}}={{R}_{\alpha }}\] done clear
  D)
             \[{{R}_{p}}={{R}_{\alpha }}\] done clear
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• question_answer107)
  An electron moving with a uniform velocity along the positive x-direction enters a magnetic field directed along the positive y-direction. The force on the electron is directed along                                                 [UPSEAT 2004]
  A)
             Positive y-direction            done clear
  B)
             Negative y-direction done clear
  C)
             Positive z-direction            done clear
  D)
             Negative z-direction done clear
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• question_answer108)
  An electron is projected along the axis of a circular conductor carrying some current. Electron will experience force                                                                       [DCE 2002]
  A)
             Along the axis done clear
  B)
             Perpendicular to the axis done clear
  C)
             At an angle of 4o with axis done clear
  D)
             No force experienced done clear
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• question_answer109)
  A very high magnetic field is applied to a stationary charge. Then the charge experiences                                              [DCE 2004]
  A)
             A force in the direction of magnetic field done clear
  B)
             A force perpendicular to the magnetic field done clear
  C)
             A force in an arbitrary direction done clear
  D)
             No force done clear
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• question_answer110)
  A electron (q = 1.6 ´ 10?19 C) is moving at right angle to the uniform magnetic field 3.534 ´ 10?5 T. The time taken by the electron to complete a circular orbit is      [MH CET 2004]
  A)
             2 ms                                           done clear
  B)
             4 ms done clear
  C)
             3 ms                                           done clear
  D)
             1 ms done clear
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• question_answer111)
  In case Hall effect for a strip having charge Q and area of cross-section A, the Lorentz force is      [DCE 2004]
  A)
             Directly proportional to Q done clear
  B)
             Inversely proportional to Q done clear
  C)
             Inversely proportional to A done clear
  D)
             Directly proportional to A done clear
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• question_answer112)
  A charged particle of mass m and charge q travels on a circular path of radius r that is perpendicular to a magnetic field B. The time taken by the particle to complete one revolution is                                  [AIEEE 2005]
  A)
             \[\frac{2\pi qB}{m}\]         done clear
  B)
             \[\frac{2\pi \,m}{q\,B}\] done clear
  C)
             \[\frac{2\pi \,m\,q}{B}\]  done clear
  D)
             \[\frac{2\pi \,{{q}^{2}}B}{m}\] done clear
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• question_answer113)
  A very long straight wire carries a current \[I\]. At the instant when a charge \[+Q\] at point \[P\] has velocity \[\overrightarrow{V}\], as shown, the force on the charge is                                      [CBSE PMT 2005]
  A)
             Opposite to OX                    done clear
  B)
             Along OX done clear
  C)
             Opposite to OY                    done clear
  D)
             Along OY done clear
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• question_answer114)
  The electron in the beam of a television tube move horizontally from south to north. The vertical component of the earth's magnetic field points down. The electron is deflected towards                                    [KCET 2005]
  A)
             West                                        done clear
  B)
             No deflection done clear
  C)
             East                                           done clear
  D)
             North to south done clear
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• question_answer115)
  An electron moves in a circular orbit with a uniform speed v. It produces a magnetic field B at the centre of the circle. The radius of the circle is proportional to      [CBSE PMT 2005]
  A)
             \[\frac{B}{v}\]                      done clear
  B)
             \[\frac{v}{R}\] done clear
  C)
             \[\sqrt{\frac{v}{B}}\]         done clear
  D)
             \[\sqrt{\frac{B}{v}}\] done clear
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• question_answer116)
  An electric field of 1500 V / m and a magnetic field of     0.40 weber / meter2 act on a moving electron. The minimum uniform speed along a straight line the electron could have is                                     [KCET 2005]
  A)
             1.6 ´ 1015 m / s                     done clear
  B)
             6 ´ 10-16 m / s done clear
  C)
             3.75 ´ 103 m / s                     done clear
  D)
             3.75 ´ 102 m / s done clear
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• question_answer117)
  An electron (mass = \[9.1\times {{10}^{-31}}\] kg; charge = \[1.6\times {{10}^{-19}}\]C) experiences no deflection if subjected to an electric field of \[3.2\times {{10}^{5}}\]V/m, and a magnetic fields of \[2.0\times {{10}^{-3}}\] Wb/m2. Both the fields are normal to the path of electron and to each other. If the electric field is removed, then the electron will revolve in an orbit of radius                                                                 [BCECE 2005]
  A)
             45 m                                         done clear
  B)
             4.5 m done clear
  C)
             0.45 m                                      done clear
  D)
             0.045 m done clear
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• question_answer118)
  An electron, moving in a uniform magnetic field of induction of intensity \[\vec{B},\] has its radius directly proportional to [DPMT 2005]
  A)
             Its charge                               done clear
  B)
             Magnetic field done clear
  C)
             Speed                                      done clear
  D)
             None of these done clear
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