JEE Main & Advanced Physics Electrostatics & Capacitance Question Bank

done Charge and Coulombs Law Total Questions - 72

• question_answer1)
  The law, governing the force between electric charges is known as          [CPMT 1972; MP PMT 2004]
  A)
             Ampere's law                       done clear
  B)
             Ohm's law done clear
  C)
             Faraday's law                        done clear
  D)
             Coulomb's law done clear
  View Solution play_arrow

• question_answer2)
  When the distance between the charged particles is halved, the force between them becomes                                [MNR 1986]
  A)
              One-fourth                           done clear
  B)
                     Half done clear
  C)
                     Double                             done clear
  D)
                     Four times done clear
  View Solution play_arrow

• question_answer3)
  There are two charges \[+1\,\mu C\] and \[+5\,\mu C\]. The ratio of the forces acting on them will be                                                                                 [CPMT 1979]
  A)
                     1 : 5                                   done clear
  B)
                     1 : 1 done clear
  C)
                     5 : 1                                   done clear
  D)
                     1 : 25 done clear
  View Solution play_arrow

• question_answer4)
  A charge \[{{q}_{1}}\] exerts some force on a second charge \[{{q}_{2}}\]. If third charge \[{{q}_{3}}\] is brought  near, the force of \[{{q}_{1}}\] exerted on \[{{q}_{2}}\]                                                            [NCERT 1971]
  A)
                     Decreases done clear
  B)
                     Increases done clear
  C)
                     Remains unchanged  done clear
  D)
  Increases if \[{{q}_{3}}\] is of the same sign as \[{{q}_{1}}\] and decreases if \[{{q}_{3}}\] is of opposite sign done clear
  View Solution play_arrow

• question_answer5)
  \[{{F}_{g}}\] and \[{{F}_{e}}\] represents gravitational and electrostatic force respectively between electrons situated at a distance 10 cm. The ratio of \[{{F}_{g}}/{{F}_{e}}\] is of the order of                [NCERT 1978; CPMT 1978]
  A)
                                                       \[{{10}^{42}}\]                      done clear
  B)
                     10 done clear
  C)
                     1                                         done clear
  D)
                     \[{{10}^{-43}}\] done clear
  View Solution play_arrow

• question_answer6)
  The ratio of the forces between two small spheres with constant charge \[(a)\] in air \[(b)\] in a medium of dielectric constant K is                                                                     [MNR 1998]
  A)
                     1 : K                                   done clear
  B)
                     K : 1 done clear
  C)
                     \[1:{{K}^{2}}\]               done clear
  D)
                     \[{{K}^{2}}:1\] done clear
  View Solution play_arrow

• question_answer7)
  A soap bubble is given a negative charge, then its radius               [MNR 1988; CPMT 1997; RPMT 1997;DCE 2000; BVP 2003]
  A)
                     Decreases done clear
  B)
                     Increases done clear
  C)
                     Remains unchanged done clear
  D)
                     Nothing can be predicted as information is insufficient done clear
  View Solution play_arrow

• question_answer8)
  Four charges are arranged at the corners of a square \[ABCD\], as shown in the adjoining figure. The force on the charge kept at the centre O is               [NCERT 1983; BHU 1999]             
  A)
                     Zero                                  done clear
  B)
                     Along the diagonal \[AC\] done clear
  C)
                     Along the diagonal \[BD\]                                           done clear
  D)
                     Perpendicular to side \[AB\] done clear
  View Solution play_arrow

• question_answer9)
  In the absence of other conductors, the surface charge density
  A)
                     Is proportional to the charge on the conductor and its surface area done clear
  B)
                     Inversely proportional to the charge and directly proportional to the surface area done clear
  C)
                     Directly proportional to the charge and inversely proportional to the surface area done clear
  D)
                     Inversely proportional to the charge and the surface area done clear
  View Solution play_arrow

• question_answer10)
  A body can be negatively charged by                                                      [CPMT 1972; AIIMS 1998]           
  A)
                     Giving excess of electrons to it done clear
  B)
                     Removing some electrons from it done clear
  C)
                     Giving some protons to it done clear
  D)
                     Removing some neutrons from it done clear
  View Solution play_arrow

• question_answer11)
  The minimum charge on an object is           
  A)
                     1 coulomb                      done clear
  B)
                     1 stat coulomb done clear
  C)
                     \[1.6\times {{10}^{-19}}\]coulomb                          done clear
  D)
                     \[3.2\times {{10}^{-19}}\]coulomb done clear
  View Solution play_arrow

• question_answer12)
  Out of gravitational, electromagnetic, Vander Waals, electrostatic and nuclear forces; which two are able to provide an attractive force between two neutrons [NCERT 1978]           
  A)
                     Electrostatic and gravitational done clear
  B)
                     Electrostatic and nuclear done clear
  C)
                     Gravitational and nuclear done clear
  D)
                     Some other forces like Vander Waals done clear
  View Solution play_arrow

• question_answer13)
  A total charge Q is broken in two parts \[{{Q}_{1}}\] and \[{{Q}_{2}}\] and they are placed at a distance \[R\] from each other. The maximum force of repulsion between them will occur, when [MP PET 1990]           
  A)
                     \[{{Q}_{2}}=\frac{Q}{R},\ {{Q}_{1}}=Q-\frac{Q}{R}\]      done clear
  B)
                     \[{{Q}_{2}}=\frac{Q}{4},\ {{Q}_{1}}=Q-\frac{2Q}{3}\] done clear
  C)
                     \[{{Q}_{2}}=\frac{Q}{4},\ {{Q}_{1}}=\frac{3Q}{4}\]         done clear
  D)
                     \[{{Q}_{1}}=\frac{Q}{2},\ {{Q}_{2}}=\frac{Q}{2}\] done clear
  View Solution play_arrow

• question_answer14)
  Three charges \[4q,\,Q\] and \[q\] are in a straight line in the position of 0, \[l/2\] and \[l\] respectively. The resultant force on \[q\] will be zero, if \[Q=\]                                                                         [CPMT 1980]
  A)
                     ? q                                     done clear
  B)
                     \[-\,2q\] done clear
  C)
                     \[-\frac{q}{2}\]             done clear
  D)
                     \[4q\] done clear
  View Solution play_arrow

• question_answer15)
  An isolated solid metallic sphere is given \[+Q\] charge. The charge will be distributed on the sphere      [MP PET 1987]
  A)
                     Uniformly but only on surface done clear
  B)
                     Only on surface but non-uniformly done clear
  C)
                     Uniformly inside the volume done clear
  D)
                     Non-uniformly inside the volume done clear
  View Solution play_arrow

• question_answer16)
  Two small spheres each having the charge \[+Q\] are suspended by insulating threads of length \[L\] from a hook. This arrangement is taken in space where there is no gravitational effect, then the angle between the two suspensions and the tension in each will be         [IIT 1986]
  A)
                     \[{{180}^{o}},\,\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{{{Q}^{2}}}{{{(2L)}^{2}}}\]               done clear
  B)
                     \[{{90}^{o}},\,\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{{{Q}^{2}}}{{{L}^{2}}}\] done clear
  C)
                     \[{{180}^{o}},\,\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{{{Q}^{2}}}{2{{L}^{2}}}\]  done clear
  D)
                     \[{{180}^{o}},\,\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{{{Q}^{2}}}{{{L}^{2}}}\] done clear
  View Solution play_arrow

• question_answer17)
  Two charges each of \[1\ coulomb\]are at a distance \[1\,km\] apart, the force between them is              [CPMT 1977; DPMT 1999]
  A)
                     \[9\times {{10}^{3}}\ Newton\] done clear
  B)
                     \[9\times {{10}^{-3}}\ Newton\]            done clear
  C)
                     \[1.1\times {{10}^{-4}}\ Newton\]                                     done clear
  D)
                     \[{{10}^{4}}\ Newton\] done clear
  View Solution play_arrow

• question_answer18)
  \[+2C\] and \[+6C\] two charges are repelling each other with a force of \[12\,N\].  If each charge is given \[-2C\] of charge, then the value of the force will be                                                                  [CPMT 1979; Kerala PMT 2002]           
  A)
                     \[4N\] (Attractive)      done clear
  B)
                     \[4N\] (Repulsive)            done clear
  C)
                     \[8N\] (Repulsive)      done clear
  D)
                                               Zero done clear
  View Solution play_arrow

• question_answer19)
  Dielectric constant of pure water is 81. Its permittivity will be                                                      [CPMT 1984]           
  A)
                     \[7.12\times {{10}^{-10}}\,MKS\] units                  done clear
  B)
                     \[8.86\times {{10}^{-12}}MKS\] units            done clear
  C)
                     \[1.02\times {{10}^{13}}\ MKS\] units                    done clear
  D)
                     Cannot be calculated done clear
  View Solution play_arrow

• question_answer20)
  There are two metallic spheres of same radii but one is solid and the other is hollow, then           [KCET 1994; BHU 1999]
  A)
                     Solid sphere can be given more charge            done clear
  B)
                     Hollow sphere can be given more charge            done clear
  C)
                     They can be charged equally (maximum) done clear
  D)
                                               None of the above done clear
  View Solution play_arrow

• question_answer21)
  In general, metallic ropes are suspended on the carriers which take inflammable material. The reason is
  A)
                     There speed is controlled done clear
  B)
                                               To keep the centre of gravity of the carrier nearer to the earth            done clear
  C)
                     To keep the body of the carrier in contact with the earth done clear
  D)
                     Nothing should be placed under the carrier done clear
  View Solution play_arrow

• question_answer22)
  Three equal charges are placed on the three corners of a square. If the force between \[{{q}_{1}}\] and \[{{q}_{2}}\]is \[{{F}_{12}}\] and that between \[{{q}_{1}}\]and \[{{q}_{3}}\] is \[{{F}_{13}}\], the ratio of magnitudes \[\frac{{{F}_{12}}}{{{F}_{13}}}\] is  [MP PET 1993]           
  A)
                     \[1/2\]                                        done clear
  B)
                     2 done clear
  C)
                     \[1/\sqrt{2}\]                done clear
  D)
                     \[\sqrt{2}\] done clear
  View Solution play_arrow

• question_answer23)
  \[ABC\] is a right angled triangle in which \[AB=3\,cm\] and \[BC=4\,cm\]. And Ð ABC = p/2. The three charges \[+15,\ +12\]  and \[-20\,e.s.u.\] are placed respectively on \[A\], \[B\] and \[C\]. The force acting on \[B\] is
  A)
                     \[125\ dynes\]                         done clear
  B)
                     \[35\ dynes\]            done clear
  C)
                     \[25\ dynes\]                done clear
  D)
                     Zero done clear
  View Solution play_arrow

• question_answer24)
  With the rise in temperature, the dielectric constant \[K\]of a liquid
  A)
                     Increases                                   done clear
  B)
                     Decreases done clear
  C)
                     Remains unchanged             done clear
  D)
                     Charges erratically done clear
  View Solution play_arrow

• question_answer25)
  Two charges \[{{q}_{1}}\]and \[{{q}_{2}}\]are placed in vacuum at a distance \[d\] and the force acting between them is \[F\]. If a medium of dielectric constant 4 is introduced around them, the force now will be                                     [MP PMT 1994]
  A)
                     \[4F\]                                          done clear
  B)
                     \[2F\]            done clear
  C)
                     \[\frac{F}{2}\]               done clear
  D)
                     \[\frac{F}{4}\] done clear
  View Solution play_arrow

• question_answer26)
  Force of attraction between two point charges \[Q\] and ? Q separated by \[d\,metre\] is \[{{F}_{e}}\]. When these charges are placed on two identical spheres of radius \[R=0.3\,d\] whose centres are \[d\,metre\]apart, the force of attraction between them is  [AIIMS 1995]           
  A)
                     Greater than \[{{F}_{e}}\]                                           done clear
  B)
                     Equal to \[{{F}_{e}}\]            done clear
  C)
                     Less than \[{{F}_{e}}\]      done clear
  D)
                     Less than \[{{F}_{e}}\] done clear
  View Solution play_arrow

• question_answer27)
  When \[{{10}^{14}}\] electrons are removed from a neutral metal sphere, the charge on the sphere becomes                                                                                     [Manipal JEE 1995]           
  A)
                     \[16\,\mu \,C\] done clear
  B)
                     \[-16\,\mu \,C\] done clear
  C)
                     \[32\,\mu \,C\]            done clear
  D)
                     \[-32\,\mu \,C\] done clear
  View Solution play_arrow

• question_answer28)
  A force \[F\] acts between sodium and chlorine ions of salt (sodium chloride) when put \[1\,cm\] apart in air. The permittivity of air and dielectric constant of water are \[{{\varepsilon }_{0}}\] and \[K\] respectively. When a piece of salt is put in water electrical force acting between sodium and chlorine ions \[1\,cm\] apart is                                     [MP PET 1995]
  A)
                     \[\frac{F}{K}\]               done clear
  B)
                     \[\frac{FK}{{{\varepsilon }_{0}}}\]            done clear
  C)
                     \[\frac{F}{K{{\varepsilon }_{0}}}\]                           done clear
  D)
                     \[\frac{F{{\varepsilon }_{0}}}{K}\] done clear
  View Solution play_arrow

• question_answer29)
  A conductor has \[14.4\times {{10}^{-19}}coulombs\] positive charge. The conductor has            (Charge on electron \[=1.6\times {{10}^{-19}}coulombs\])           
  A)
                     9 electrons in excess             done clear
  B)
                     27 electrons in short            done clear
  C)
                     27 electrons in excess       done clear
  D)
                                               9 electrons in short done clear
  View Solution play_arrow

• question_answer30)
  The value of electric permittivity of free space is                                                                         [MP PET 1996; RPET 2001]           
  A)
                     \[9\times {{10}^{9}}N{{C}^{2}}/{{m}^{2}}\]         done clear
  B)
                                               \[8.85\times {{10}^{-12}}N{{m}^{2}}/{{C}^{2}}sec\] done clear
  C)
                     \[8.85\times {{10}^{-12}}{{C}^{2}}/N{{m}^{2}}\]             done clear
  D)
                     \[9\times {{10}^{9}}{{C}^{2}}/N{{m}^{2}}\] done clear
  View Solution play_arrow

• question_answer31)
  Two similar spheres having \[+\,q\] and \[-\,q\] charge are kept at a certain distance. \[F\] force acts between the two. If in the middle of two spheres, another similar sphere having \[+\,q\] charge is kept, then it experience a force in magnitude and direction as                               [MP PET 1996]
  A)
                     Zero having no direction            done clear
  B)
                     \[8F\] towards \[+\,q\] charge            done clear
  C)
                     \[8F\] towards \[-\,q\] charge done clear
  D)
                     \[4F\] towards \[+\,q\] charge done clear
  View Solution play_arrow

• question_answer32)
  A charge \[Q\] is divided into two parts of \[q\] and \[Q-q\]. If the coulomb repulsion between them when they are separated is to be maximum, the ratio of \[\frac{Q}{q}\] should be          [MP PET 1997]
  A)
                     2 done clear
  B)
                     \[1/2\] done clear
  C)
                     4            done clear
  D)
                     \[1/4\] done clear
  View Solution play_arrow

• question_answer33)
  Number of electrons in one coulomb of charge will be [MP PMT/PET 1998; Pb. PMT 1999; AIIMS 1999; RPET 2001]           
  A)
                     \[5.46\times {{10}^{29}}\]                                                      done clear
  B)
                     \[6.25\times {{10}^{18}}\] done clear
  C)
                     \[1.6\times {{10}^{+19}}\]                                           done clear
  D)
                     \[9\times {{10}^{11}}\] done clear
  View Solution play_arrow

• question_answer34)
  When air is replaced by a dielectric medium of constant \[k\], the maximum force of attraction between two charges separated by a distance                                       [CBSE PMT 1999]
  A)
                     Decreases \[k\] times       done clear
  B)
                     Remains unchanged done clear
  C)
                     Increases \[k\] times done clear
  D)
                     Increases \[{{k}^{-1}}\] times done clear
  View Solution play_arrow

• question_answer35)
  A glass rod rubbed with silk is used to charge a gold leaf electroscope and the leaves are observed to diverge. The electroscope thus charged is exposed to X-rays for a short period. Then                                                [AMU 1995]
  A)
                     The divergence of leaves will not be affected            done clear
  B)
                     The leaves will diverge further done clear
  C)
                     The leaves will collapse            done clear
  D)
                     The leaves will melt done clear
  View Solution play_arrow

• question_answer36)
  One metallic sphere \[A\] is given positive charge whereas another identical metallic sphere \[B\] of exactly same mass as of \[A\]is given equal amount of negative charge. Then [AMU 1995; RPET 2000; CPMT 2000]           
  A)
                     Mass of \[A\] and mass of \[B\] still remain equal            done clear
  B)
                     Mass of \[A\] increases            done clear
  C)
                     Mass of \[B\] decreases            done clear
  D)
                     Mass of \[B\] increases done clear
  View Solution play_arrow

• question_answer37)
  The force between two charges \[0.06\,m\] apart is \[5\,N\]. If each charge is moved towards the other by \[0.01\,m\], then the force between them will become        [SCRA 1994]
  A)
                     \[7.20\,N\]                     done clear
  B)
                                               \[11.25\,N\] done clear
  C)
                     \[22.50\,N\]                              done clear
  D)
                     \[45.00\,N\] done clear
  View Solution play_arrow

• question_answer38)
  Two charged spheres separated at a distance d exert a force \[F\]on each other. If they are immersed in a liquid of dielectric constant 2, then what is the force (if all conditions are same)                   [AIIMS 1997; MH CET 2003]
  A)
                     \[\frac{F}{2}\] done clear
  B)
                                               \[F\] done clear
  C)
                     \[2F\]                               done clear
  D)
                     \[4F\] done clear
  View Solution play_arrow

• question_answer39)
  Two point charges \[+3\mu C\] and \[+8\mu C\] repel each other with a force of \[40N\]. If a charge of \[-5\mu C\]is added to each of them, then the force between them will become                                                               [SCRA 1998; JIPMER 2000]           
  A)
                     \[-10N\]                          done clear
  B)
                                               \[+10N\] done clear
  C)
                     \[+20N\]                                    done clear
  D)
                     \[-20N\] done clear
  View Solution play_arrow

• question_answer40)
  When \[{{10}^{19}}\] electrons are removed from a neutral metal plate,  the electric charge on it is [Karnataka CET (Engg./Med.) 1999]
  A)
             ? 1.6 C                                      done clear
  B)
             + 1.6 C done clear
  C)
             \[{{10}^{+19}}C\]                done clear
  D)
             \[{{10}^{19}}C\] done clear
  View Solution play_arrow

• question_answer41)
  Electric charges of \[1\mu C,\,-1\mu C\] and \[2\mu C\] are placed in air at the corners A, B and C respectively of an equilateral triangle ABC having length of each side 10 cm. The resultant force on the charge at C is                        [EAMCET (Engg.) 2000]
  A)
             0.9 N                                         done clear
  B)
  1.8 N done clear
  C)
             2.7 N done clear
  D)
             3.6 N done clear
  View Solution play_arrow

• question_answer42)
  Charge on \[\alpha \]-particle is                                                                [MH CET 2000]
  A)
             \[4.8\times {{10}^{-19}}C\]     done clear
  B)
             \[1.6\times {{10}^{-19}}C\] done clear
  C)
             \[3.2\times {{10}^{-19}}C\]     done clear
  D)
             \[6.4\times {{10}^{-19}}C\] done clear
  View Solution play_arrow

• question_answer43)
  Two small conducting spheres of equal radius have charges \[+10\mu C\] and \[-20\mu C\] respectively and placed at a distance \[R\] from each other experience force \[{{F}_{1}}\]. If they are brought in contact and separated to the same distance, they experience force \[{{F}_{2}}\]. The ratio of \[{{F}_{1}}\] to \[{{F}_{2}}\] is [MP PMT 2001]
  A)
             1 : 8                                           done clear
  B)
             ? 8 : 1 done clear
  C)
             1 : 2                                           done clear
  D)
             ? 2 : 1 done clear
  View Solution play_arrow

• question_answer44)
  Two charges each equal to \[2\mu C\] are 0.5m apart. If both of them exist inside vacuum, then the force between them is [CPMT 2001]
  A)
             1.89 N                                      done clear
  B)
             2.44 N done clear
  C)
             0.144 N                                    done clear
  D)
             3.144 N done clear
  View Solution play_arrow

• question_answer45)
  Two charges are at a distance ?d? apart. If a copper plate (conducting medium) of thickness \[\frac{d}{2}\] is placed between them, the effective force will be [UPSEAT 2001; J & K CET 2005]
  A)
             2F   done clear
  B)
             F / 2 done clear
  C)
             0     done clear
  D)
             \[\sqrt{2}F\] done clear
  View Solution play_arrow

• question_answer46)
  Two electrons are separated by a distance of 1Å. What is the coulomb force between them                                        [MH CET 2002]
  A)
             \[2.3\times {{10}^{-8}}\]N      done clear
  B)
             \[4.6\times {{10}^{-8}}\]N done clear
  C)
             \[1.5\times {{10}^{-8}}\]N      done clear
  D)
             None of these done clear
  View Solution play_arrow

• question_answer47)
  Two copper balls, each weighing 10g are kept in air 10 cm apart. If one electron from every \[{{10}^{6}}\] atoms is transferred from one ball to the other, the coulomb force between them is (atomic weight of copper is 63.5)     [KCET 2002]
  A)
             \[2.0\times {{10}^{10}}\]N      done clear
  B)
             \[2.0\times {{10}^{4}}\]N done clear
  C)
             \[2.0\times {{10}^{8}}\]N done clear
  D)
             \[2.0\times {{10}^{6}}\]N done clear
  View Solution play_arrow

• question_answer48)
  A solid conducting sphere of radius a has a net positive charge 2Q. A conducting spherical shell of inner radius \[b\] and outer radius c is concentric with the solid sphere and has a net charge ? Q. The surface charge density on the inner and outer surfaces of the spherical shell will be  [AMU 2002]
  A)
             \[-\frac{2Q}{4\pi {{b}^{2}}},\frac{Q}{4\pi {{c}^{2}}}\] done clear
  B)
             \[-\frac{Q}{4\pi {{b}^{2}}},\frac{Q}{4\pi {{c}^{2}}}\] done clear
  C)
             \[0,\frac{Q}{4\pi {{c}^{2}}}\] done clear
  D)
             None of the above done clear
  View Solution play_arrow

• question_answer49)
  Three charges each of magnitude q are placed at the corners of an equilateral triangle, the electrostatic force on the charge placed at the center is (each side of triangle is L) [DPMT 2002]
  A)
             Zero                                          done clear
  B)
             \[\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{{{q}^{2}}}{{{L}^{2}}}\] done clear
  C)
             \[\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{3{{q}^{2}}}{{{L}^{2}}}\]     done clear
  D)
             \[\frac{1}{12\pi {{\varepsilon }_{0}}}\frac{{{q}^{2}}}{{{L}^{2}}}\] done clear
  View Solution play_arrow

• question_answer50)
  Two charges placed in air repel each other by a force of \[{{10}^{-4}}N\]. When oil is introduced between the charges, the force becomes \[2.5\times {{10}^{-5}}N\]. The dielectric constant of oil is                                                               [MP PET 2003]
  A)
             2.5  done clear
  B)
             0.25 done clear
  C)
             2.0  done clear
  D)
             4.0 done clear
  View Solution play_arrow

• question_answer51)
  Three charges are placed at the vertices of an equilateral triangle of side ?a? as shown in the following figure. The force experienced by the charge placed at the vertex A in a direction normal to BC is                                  [AIIMS 2003]
  A)
             \[{{Q}^{2}}/(4\pi {{\varepsilon }_{0}}{{a}^{2}})\] done clear
  B)
             \[-{{Q}^{2}}/(4\pi {{\varepsilon }_{0}}{{a}^{2}})\] done clear
  C)
             Zero done clear
  D)
             \[{{Q}^{2}}/(2\pi {{\varepsilon }_{0}}{{a}^{2}})\] done clear
  View Solution play_arrow

• question_answer52)
  Two particle of equal mass \[m\] and charge \[q\] are placed at a distance of 16 cm. They do not experience any force. The value of \[\frac{q}{m}\] is                              [MP PET 2003]
  A)
             l       done clear
  B)
             \[\sqrt{\frac{\pi {{\varepsilon }_{0}}}{G}}\] done clear
  C)
             \[\sqrt{\frac{G}{4\pi {{\varepsilon }_{0}}}}\]              done clear
  D)
             \[\sqrt{4\pi {{\varepsilon }_{0}}G}\] done clear
  View Solution play_arrow

• question_answer53)
  When a glass rod is rubbed with silk, it              [MP PET 2003]
  A)
             Gains electrons from silk done clear
  B)
             Gives electrons to silk done clear
  C)
             Gains protons from silk    done clear
  D)
             Gives protons to silk done clear
  View Solution play_arrow

• question_answer54)
  An electron is moving round the nucleus of a hydrogen atom in a circular orbit of radius r. The coulomb force \[\overrightarrow{F}\] between the two is  (Where \[K=\frac{1}{4\pi {{\varepsilon }_{0}}}\])      [CBSE PMT 2003]
  A)
             \[-K\frac{{{e}^{2}}}{{{r}^{3}}}\hat{r}\]                           done clear
  B)
             \[K\frac{{{e}^{2}}}{{{r}^{3}}}\vec{r}\] done clear
  C)
             \[-K\frac{{{e}^{2}}}{{{r}^{3}}}\vec{r}\]                          done clear
  D)
             \[K\frac{{{e}^{2}}}{{{r}^{2}}}\hat{r}\] done clear
  View Solution play_arrow

• question_answer55)
  A body has ? 80 micro coulomb of charge. Number of additional electrons in it will be                     [MP PMT 2003]
  A)
             \[8\times {{10}^{-5}}\]      done clear
  B)
             \[80\times {{10}^{-17}}\] done clear
  C)
             \[5\times {{10}^{14}}\]     done clear
  D)
             \[1.28\times {{10}^{-17}}\] done clear
  View Solution play_arrow

• question_answer56)
  Two point charges placed at a certain distance r in air exert a force F on each other. Then the distance r' at which these charges will exert the same force in a medium of dielectric constant k is given by              [EAMCET 1990; MP PMT 2001]
  A)
             r      done clear
  B)
             r/k done clear
  C)
             \[r/\sqrt{k}\]                        done clear
  D)
             \[r\sqrt{k}\] done clear
  View Solution play_arrow

• question_answer57)
  Dielectric constant for metal is         [MP PMT/PET 1998]
  A)
             Zero done clear
  B)
             Infinite done clear
  C)
             1 done clear
  D)
             Greater than 1 done clear
  View Solution play_arrow

• question_answer58)
  A charge of Q coulomb is placed on a solid piece of metal of irregular shape. The charge will distribute itself                                                                                          [MP PMT 1991]           
  A)
                     Uniformly in the metal object            done clear
  B)
                     Uniformly on the surface of the object            done clear
  C)
                     Such that the potential energy of the system is minimized done clear
  D)
                     Such that the total heat loss is minimized done clear
  View Solution play_arrow

• question_answer59)
  Five balls numbered 1 to 5 are suspended using separate threads. Pairs (1, 2), (2, 4) and (4, 1) show electrostatic attraction, while pair (2, 3) and (4, 5) show repulsion. Therefore ball 1 must be   [NCERT 1980; MP PMT 2003]
  A)
                     Positively charged       done clear
  B)
                     Negatively charged done clear
  C)
                     Neutral                            done clear
  D)
                     Made of metal done clear
  View Solution play_arrow

• question_answer60)
  Equal charges \[q\] are placed at the four corners \[A,\,B,\,C,\,D\] of a square of length \[a\]. The magnitude of the force on the charge at B will be                                                                  [MP PMT 1994; DPMT 2001]
  A)
                     \[\frac{3{{q}^{2}}}{4\pi {{\varepsilon }_{0}}{{a}^{2}}}\]                           done clear
  B)
                     \[\frac{4{{q}^{2}}}{4\pi {{\varepsilon }_{0}}{{a}^{2}}}\]            done clear
  C)
                     \[\left( \frac{1+2\sqrt{2}}{2} \right)\frac{{{q}^{2}}}{4\pi {{\varepsilon }_{0}}{{a}^{2}}}\]               done clear
  D)
                     \[\left( 2+\frac{1}{\sqrt{2}} \right)\frac{{{q}^{2}}}{4\pi {{\varepsilon }_{0}}{{a}^{2}}}\] done clear
  View Solution play_arrow

• question_answer61)
  Two identical conductors of copper and aluminium are placed in an identical electric fields. The magnitude of induced charge in the aluminium will be       [AIIMS 1999]
  A)
             Zero done clear
  B)
             Greater than in copper done clear
  C)
             Equal to that in copper     done clear
  D)
             Less than in copper done clear
  View Solution play_arrow

• question_answer62)
  Two spherical conductors B and C having equal radii and carrying equal charges in them repel each other with a force F when kept apart at some distance. A third spherical conductor having same radius as that of B but uncharged is brought in contact with B, then brought in contact with C and finally removed away from both. The new force of repulsion between B and C is                                   [AIEEE 2004]
  A)
                     \[F/4\]                             done clear
  B)
                     \[3F/4\] done clear
  C)
                     \[F/8\]                             done clear
  D)
                     \[3F/8\] done clear
  View Solution play_arrow

• question_answer63)
  When a body is earth connected, electrons from the earth flow into the body. This means the body is?.. [KCET 2004]
  A)
                     Unchanged                               done clear
  B)
                     Charged positively done clear
  C)
  Charged negatively                       done clear
  D)
  An insulator done clear
  View Solution play_arrow

• question_answer64)
  The charges on two sphere are\[+7\,\mu C\] and \[-5\,\mu C\] respectively. They experience a force F. If each of them is given and additional charge of \[-2\,\mu C\], the new force of attraction will be [RPET 2002]           
  A)
                     F done clear
  B)
                     F / 2            done clear
  C)
                     \[F/\sqrt{3}\]                done clear
  D)
                     2F done clear
  View Solution play_arrow

• question_answer65)
  The ratio of electrostatic and gravitational forces acting between electron and proton separated by a distance \[5\times {{10}^{-11}}m,\] will be (Charge on electron \[=\text{ 1}.\text{6}\times \text{1}{{0}^{\text{19}}}C\], mass of electron \[=\text{ 9}.\text{1}\times \text{1}{{0}^{\text{31}}}kg\], mass of proton = \[1.6\times {{10}^{-27}}kg,\] \[\,G=6.7\times {{10}^{-11}}\,N{{m}^{2}}/k{{g}^{2}})\]                  [RPET 1997; Pb PMT 2003]
  A)
                     \[\text{2}.\text{36}\times \text{1}{{0}^{\text{39}}}\] done clear
  B)
                     \[\text{2}.\text{36}\times \text{1}{{0}^{40}}\]            done clear
  C)
              \[\text{2}.\text{34}\times \text{1}{{0}^{41}}\]         done clear
  D)
                     \[\text{2}.\text{34}\times \text{1}{{0}^{42}}\] done clear
  View Solution play_arrow

• question_answer66)
  Two point charges \[\text{3}\times \text{1}{{0}^{\text{6}}}C\]and \[\text{8}\times \text{1}{{0}^{\text{6}}}C\] repel each other by a force of \[\text{6}\times \text{1}{{0}^{\text{3}}}N\]. If each of them is given an additional charge \[\text{ 6}\times \text{1}{{0}^{\text{6}}}C\], the force between them will be     [DPMT 2003]
  A)
                     \[2.4\times \text{1}{{0}^{3}}N\] (attractive)       done clear
  B)
                     \[2.4\times \text{1}{{0}^{9}}N\] (attractive) done clear
  C)
                     \[\text{1}.\text{5}\times \text{1}{{0}^{\text{3}}}N\] (repulsive)                        done clear
  D)
                     \[\text{1}.\text{5}\times \text{1}{{0}^{\text{3}}}N\] (attractive) done clear
  View Solution play_arrow

• question_answer67)
  Two equally charged, identical metal spheres A and B repel each other with a force 'F'. The spheres are kept fixed with a distance 'r' between them. A third identical, but uncharged sphere C is brought in contact with A and then placed at the mid-point of the line joining A and B. The magnitude of the net electric force on C is                                [UPSEAT 2004; DCE 2005]
  A)
                     F                                         done clear
  B)
                     3F/4            done clear
  C)
                     F/2                                     done clear
  D)
                     F/4 done clear
  View Solution play_arrow

• question_answer68)
  Two charges of equal magnitudes and at a distance r exert a force F on each other. If the charges are halved and distance between them is doubled, then the new force acting on each charge is                                               [DCE 2004]
  A)
                     F / 8                                              done clear
  B)
                     F / 4            done clear
  C)
                     4 F                                      done clear
  D)
                     F / 16 done clear
  View Solution play_arrow

• question_answer69)
  An infinite number of charges, each of charge 1 mC, are placed on the x-axis with co-ordinates x = 1, 2, 4, 8, ....¥. If a charge of 1 C is kept at the origin, then what is the net force acting on 1 C charge                                              [DCE 2004]
  A)
                     9000 N                              done clear
  B)
                     12000 N done clear
  C)
                     24000 N                                      done clear
  D)
                     36000 N done clear
  View Solution play_arrow

• question_answer70)
  The number of electrons in 1.6 C charge will be [RPET 2004]           
  A)
                     \[{{10}^{19}}\] done clear
  B)
                     \[{{10}^{20}}\]            done clear
  C)
                     \[1.1\times {{10}^{19}}\] done clear
  D)
                     \[1.1\times {{10}^{2}}\] done clear
  View Solution play_arrow

• question_answer71)
  Four metal conductors having different shapes 1.        A sphere                                 2.        Cylindrical 3.        Pear                                          4.        Lightning conductor Are mounted on insulating stands and charged. The one which is best suited to retain the charges for a longer time is [KCET 2005]
  A)
             1     done clear
  B)
             2 done clear
  C)
             3     done clear
  D)
             4 done clear
  View Solution play_arrow

• question_answer72)
  Identify the wrong statement in the following. Coulomb's law correctly describes the electric force that                [KCET 2005]
  A)
             Binds the electrons of an atom to its nucleus done clear
  B)
             Binds the protons and neutrons in the nucleus of an atom done clear
  C)
             Binds atoms together to form molecules done clear
  D)
                     Binds atoms and molecules together to form solids done clear
  View Solution play_arrow