0
question_answer1) The electric charge of any body is actually a surplus or deficit of electrons. Why not protons?
question_answer2) When a glass rod is rubbed with silk, both acquire charges. What is the source of their electrification?
question_answer3) Is the mass of a body affected on charging?
question_answer4) Two identical metallic spheres of exactly equal masses are taken. One is given a positive charge q coulombs and other an equal negative charge. Are their masses after charging equal?
question_answer5) A positively charged rod repels a suspended object. Can we conclude that the object is positively charged?
question_answer6) A positively charged rod attracts a suspended object. Can we conclude that the object is negatively charged?
question_answer7) How does a positively charged glass rod attract a neutral piece of paper?
question_answer8) Can two like charges attract each other? If yes, how?
question_answer9) Why do the gramophone records get covered with dust easily?
question_answer10) An ebonite rod held in hand can be charged by rubbing with flannel but a copper rod cannot be charged like this. Why?
question_answer11) Electrostatic experiments do not work well on humid days. Give reason.
question_answer12) A comb run through one's dry hair attracts small bits of paper. Why? What happens if the hair is wet or if it is a rainy day?
question_answer13) Ordinary rubber is an insulator. But the special rubber tyres of aircrafts are made slightly conducting. Why is this necessary?
question_answer14) Vehicles carrying inflammable materials usually have metallic ropes touching the ground during motion. Why?
question_answer15) An inflated balloon is charged by rubbing with fur. Will it stick readily to a conducting wall or to an insulating wall? Give reason.
question_answer16) A metal sphere is fixed on a smooth horizontal insulating plate. Another metal sphere is placed a small distance away. If the fixed sphere is given a charge, how will the other sphere react?
question_answer17) Is there some way of producing high voltage on your body without getting a shock?
question_answer18) A charged rod attracts bits of dry cork which after touching the rod, often jump away from it violently. Why?
question_answer19) What does \[{{q}_{1}}+{{q}_{2}}=0\] signify in electrostatics? Or Two charges \[{{q}_{1}}\] and\[{{q}_{2}}\], separated by a small distance satisfy the equation \[{{q}_{1}}+{{q}_{2}}=0\]. What does it tell about the charges?
question_answer20) Name the experiment which established the quantum nature of electric charge.
question_answer21) Can a body have a charge of \[\mathbf{0}\mathbf{.8 \times 1}{{\mathbf{0}}^{\mathbf{-19}}}\mathbf{~~C}\] Justify your answer by comment?
question_answer22) If the distance between two equal point charges is doubled and their individual charges are also doubled, what would happen to the force between them?
question_answer23) The electrostatic force between two charges is a central force. Why?
question_answer24) How is the Coulomb force between two charges affected by the presence of a third charge?
question_answer25) How does the force between two point charges change, if the dielectric constant of the medium in which they are kept, increases?
question_answer26) Force between two point charges kept at a distant d apart in air is F. If these charges are kept at the same distance in water, how does the electric force between them change?
question_answer27) The dielectric constant of water is 80. What is its permittivity?
question_answer28) Give an example to illustrate that electrostatic forces are much stronger than gravitational forces.
question_answer29) Two electrically charged particles, having charges of different magnitude, when placed at a distance 'd' from each other, experience a force of attraction 'F'. These two particles are put in contact and again placed at the same distance from each other. What is the nature of new force between them? Is the magnitude of the force of interaction between them now more or less than F?
question_answer30) An electron moves along a metal tube with variable cross-section, as shown in Fig. How will its velocity change when it approaches the neck of the tube?
question_answer31) Why should a test charge be of negligibly small magnitude?
question_answer32) In defining electric field due to a point charge, the test charge has to be vanishingly small. How this condition can be justified, when we know that charge less than that on an electron or a proton is not possible?
question_answer33) What is the advantage of introducing the concept of electric field?
question_answer34) How do charges interact?
question_answer35) An electron and a proton are kept in the same electric field. Will they experience same force and have same acceleration?
question_answer36) Why direction of an electric field is taken outward (away) for a positive charge and inward (towards) for a negative charge?
question_answer37) A charged particle is free to move in an electric field. Will it always move along an electric field?
question_answer38) A small test charge is released at rest at a point in an electrostatic field configuration. Will it travel along the line of force?
question_answer39) Why do charges reside on the surface of the conductor?
question_answer40) Why is electric field zero inside a charged conductor?
question_answer41) Can electric lines of force form closed loops? Give reason for your answer.
question_answer42) Do the electric lines of force really exist? What is about the field they represent?
question_answer43) Draw lines of force to represent a uniform electric field.
question_answer44) Fig. shows electric lines of force due to point charges \[{{q}_{1}}\] and \[{{q}_{2}}\] placed at points A and B respectively. Write the nature of charge on them.
question_answer45) A positive point charge \[\mathbf{(+q)}\] is kept in the vicinity of an uncharged conducting plate. Sketch electric field lines originating from the point charge on to the surface of the plate.
question_answer46) Why is it necessary that the field lines from a point charge placed in the vicinity of a conductor must be normal to the conductor at every point.
question_answer47) Fig. shows two large metal plates, \[{{P}_{1}}\]and \[{{\mathbf{P}}_{\mathbf{2}}}\] tightly held against each other and placed between two equal and unlike point charges perpendicular to the line joining them. (i) What will happen to the plates when they are released? (ii) Draw the pattern of the electric field lines for the system.
question_answer48) In the electric field shown in Fig. the electric field lines on the left have twice the separation as that between those on the right. If the magnitude of the field at point A is\[\mathbf{40N}{{\mathbf{C}}^{\mathbf{-1}}}\], calculate the force experienced by a proton placed at point A. Also find the magnitude of electric field at point B.
question_answer49) The electric lines of force tend to contract lengthwise and expand laterally. What do they indicate?
question_answer50) A point charge placed at any point on the axis of an electric dipole at some large distance experiences a force F. What will be the force acting on the point charge when its distance from the dipole is doubled?
question_answer51) As shown in Fig. a thin spherical shell carries a charge \[\mathbf{Q}\] on its surface. A point charge \[\mathbf{Q}\text{ }/\text{ }\mathbf{2}\]is placed at its centre O and another charge \[\mathbf{2Q}\] placed outside. If all the charges are positive, what will be the force on the charge at the centre?
question_answer52) What is the number of electric lines of force that radiate outwards from one coulomb of charge in vacuum?
question_answer53) Consider the situation shown in Fig. What are the signs of\[{{q}_{1}}\] and \[{{q}_{2}}\] ? If the lines are drawn in proportion to the charge, what is the ratio \[{{\mathbf{q}}_{\mathbf{1}}}\mathbf{/}{{\mathbf{q}}_{\mathbf{2}}}\]?
question_answer54) An arbitrary surface encloses a dipole. What is the electric flux through this surface?
question_answer55) The force on an electron kept in an electric field in a particular direction is F. What will be the magnitude and direction of the force experienced by a proton at the same point in the field? Mass of the proton is 1836 times the mass of the electron.
question_answer56) Figure shows three charges \[+2q,-q\] and\[+3q\]. Two charges \[+2q\] and \[-q\] are enclosed with in a surface 'S'. What is the electric flux due to this configuration through the surface 'S'?
question_answer57) Five balls, numbered 1 to 5 are suspended using separate threads. Pairs (1, 2), (2, 4), (4, 1) show electrostatic attraction, while pairs (2, 3) and (4, 5) show repulsion. What is the nature of charge on ball 1?
question_answer58) A charged metallic sphere A is suspended by a nylon thread. Another charged metallic sphere B carried by an insulating handle is brought close to A such that the distance between their centres is 10 cm as shown in Fig. (a). The resulting repulsion of A is noted (for example, by shining a beam of light and measuring the deflection of its shadow on a calibrated screen). Spheres A and B are touched by uncharged spheres C and D, respectively as shown in Fig. (b).C and D are then removed and B is brought closer to A to a distance of 5.0 cm between their centres, as shown in Fig. (c). What is the expected repulsion of A on the basis of Coulomb's law? Spheres A and C and spheres B and D have identical sizes. Ignore the sizes of A and B in comparison to the separation between their centres.
question_answer59) State the limitations of Coulomb's law in electrostatics. Is Coulomb's law in electrostatics valid in all situations?
question_answer60) Compare electrostatic and gravitational interactions.
question_answer61) Distinguish between electric charge and mass.
question_answer62) What is an electric line of force? What is its importance?
question_answer63) Represent the surface distribution of charge for a square metal plate by using dashes in such a way that the greater the surface density of charge, the farther away are the dashes from the plate.
question_answer64) Two point electric charges of unknown magnitude and sign are placed a distance 'd' apart. The electric field intensity is zero at a point, not between the charges but on the line joining them. Write the essential conditions for this to happen.
question_answer65) The electric field E due to a point charge F at any point is defined as\[\underset{q\to 0}{\mathop{\lim }}\,\frac{F}{q},\] where\[q\] is the test charge and F is the force acting on it. What is the physical significance of \[\underset{q\to 0}{\mathop{\lim }}\,\] in this field expression? Draw the electric lines of a point charge \[\mathbf{Q}\] when (i) \[\mathbf{Q>0}\] and(ii) \[\mathbf{Q}<\mathbf{0}.\]
question_answer66) A charge Q located at a point \[\vec{r}\] is in equilibrium under the combined electric field of three charges \[{{\mathbf{q}}_{\mathbf{1}}}\mathbf{,}{{\mathbf{q}}_{\mathbf{2}}}\mathbf{,}{{\mathbf{q}}_{\mathbf{3}}}\mathbf{.}\]charges \[{{\mathbf{q}}_{\mathbf{1}}}\mathbf{,}{{\mathbf{q}}_{\mathbf{2}}}\] are located at points \[{{\mathbf{\vec{r}}}_{\mathbf{1}}}\] and \[{{\mathbf{\vec{r}}}_{2}}\] respectively, find the direction of the force on Q, due to \[{{\mathbf{q}}_{\mathbf{3}}}\] in terms of\[{{\mathbf{q}}_{\mathbf{1}}}\mathbf{,}{{\mathbf{q}}_{\mathbf{2}}}\mathbf{,}{{\mathbf{\vec{r}}}_{\mathbf{1}}}\mathbf{,}{{\mathbf{\vec{r}}}_{\mathbf{2}}}\] and \[\mathbf{\vec{r}}\].
question_answer67) Two point charges \[+q\] and \[-q\] are placed a 'd' distance apart. Draw the line on which the resultant field is parallel to the line joining the two charges.
question_answer68) Draw a diagram to show lines of force in a plane containing two equal point charges of opposite sign separated by a small distance. Giving reason, indicate on the diagram a point where a small positive charge experiences a force parallel to the line joining the two charges.
question_answer69) What is meant by the statement that the electric field of a point charge has spherical symmetry whereas that of an electric dipole is cylindrically symmetric?
question_answer70) An electric dipole free to move is placed in a uniform electric field. Explain along with diagram its motion when it is placed, (a) parallel to the field, (b) perpendicular to the field.
question_answer71) An electric dipole is a pair of equal and opposite charges, separated by a small fixed distance between them. The dipole is free to move. What is the action on it, when it is placed in (i) a uniform electric field, and (ii) a non-uniform electric field?
question_answer72) An electric dipole of dipole moment \[\mathbf{\vec{p}}\] is placed in a uniform electric field\[\mathbf{\vec{E}}\]. Write the expression for the torque \[\mathbf{\vec{\tau }}\] experienced by the dipole. Identify two pairs of perpendicular vectors in the expression. Show diagrammatically the orientation of the dipole in the field for which the torque is (i) maximum (ii) half the maximum value (iii) zero.
question_answer73) Two small identical electrical dipoles AB and CD, each of dipole moment\[\mathbf{'p'}\] are kept at an angle of 120° as shown in Fig. What is the resultant dipole moment of this combination? If this system is subjected to electric field (\[\mathbf{\vec{E}}\]) directed along \[\mathbf{+X}\] direction, what will be the magnitude and direction of the torque acting on this?
question_answer74) Define electric flux. Write its SI units. A spherical balloon carries a charge that is uniformly distributed over its surface. As the balloon is blown up and increases in size, how does the total electric flux coming out of the surface change? Give reason.
question_answer75) A sphere \[{{\mathbf{S}}_{\mathbf{1}}}\] of radius\[{{\mathbf{r}}_{\mathbf{1}}}\] encloses a charge Q. If there is another concentric sphere of radius\[{{\mathbf{r}}_{\mathbf{2}}}\mathbf{(}{{\mathbf{r}}_{\mathbf{2}}}\mathbf{>}{{\mathbf{r}}_{\mathbf{1}}}\mathbf{)}\] there be no additional charges between \[{{\mathbf{S}}_{\mathbf{1}}}\] and \[{{\mathbf{S}}_{\mathbf{2}}}\] find the ratio of the electric flux through \[{{\mathbf{S}}_{\mathbf{1}}}\] and \[{{\mathbf{S}}_{\mathbf{2}}}\]
question_answer76) A spherical rubber balloon carries a charge that is uniformly distributed over its surface. As the balloon is blown up; how does E vary for points (i) inside the balloon, (ii) on the surface of the balloon and (iii) outside the balloon?
Please Wait you are being redirected....
You need to login to perform this action.You will be redirected in 3 sec
OTP has been sent to your mobile number and is valid for one hour
Your mobile number is verified.