Class 12 Physics Chapter 2 MCQ with Answers Electrostatic Potential and Capacitance MCQs
Question 1. Which of the following statement is true?
(a) Electrostatic force is a conservative force.
(b) Potential at a point is the work done per unit charge in bringing a charge from any point to infinity.
(c) Electrostatic force is non-conservative
(d) Potential is the productof charge and work.
Answer: (a) Electrostatic force is a conservative force
Question 2. The dimensions of fall of potential per unit distance are given by:
(a) [MLT-3 A-1]
Answer: (c) [ML2T-2A-3]
Question 3. A positively charged particle is released from rest in an uniform electric field. The electric potential energy of the charge
(a) remains a constant because the electric field is uniform.
(b) increases because the charge moves along the electric field.
(c) decreases because the charge moves along the electric field.
(d) decreases because the charge moves opposite to the electric field
Answer: (c) decreases because the charge moves along the electric field.
Question 4. Dielectric strength of a medium is 2 KV mm-1. What is the maximum potential difference that can be set up across a 50 µm specimen without puncturing it.
(a) 10 V
(b) 100 V
(c) 1000 V
(d) 10,000 V
Answer: (b) 100 V
Question 5. 1 volt is equivalent to
Answer: (c) joule/coulomb
Question 6. Which of the following is blocked by a capacitor ?
(c) Both A.C. and D.C.
(d) Neither A.C. nor D. C
Answer: (b) D.C
Question 7. Equipotentials at a great distance from a collection of charges whose total sum is not zero are approximately
Answer: (a) spheres
Question 8. A charge q is distributed over two spheres of radii r1 and r2 such that their surface densities are equal. What is the ratio of their potential.
(d) none of these
Answer: (a) r1/r2
Question 9. The work done in bringing a unit positive charge from infinite distance to a point at distance x from a positive charge Q is W. Then the potential at that point is
Answer: (b) W
Question 10. Two copper spheres of the same radius, one solid and the other hollow, are charged to the same potential. Which will have more charge?
(a) Solid sphere
(b) Hollow sphere
(c) Both will have an equal charge
(d) None of these
Answer: (c) Both will have an equal charge
Question 11. Two small spheres each carrying a charge q are placed r metre apart. If one of the spheres is taken around the other one in a circular path of radius r, the work done will be equal to
(a) force between them × r
(b) force between them × 2πr
(c) force between them/2πr
Answer: (d) zero
Question 12. A hollow metal sphere of radius 5 cm is charged such that the potential on its surface is 10 V. The potential at a distance of 2 cm from the centre of sphere is:
(b) 10 V
(c) 5 V
(d) 10/3 V
Answer: (b) 10 V
Question 13. Consider a uniform electric field in the z-direction. The potential is a constant
(a) for any x for a given z
(b) for any y for a given z
(c) on the x-y plane for a given z
(d) all of these
Answer: (d) all of these
Question 14. The capacitance of a capacitor will decrease if we introduce a slab of:
(d) None of these
Answer: (d) None of these
Question 15. The electric potential V at any point O (x, y, z all in metres) in space is given by V = 4x² volt. The electric field at the point (1 m, 0, 2 m) in volt/metre is
(a) 8 along negative x-axis
(b) 8 along positive x-axis
(c) 16 along negative x-axis
(d) 16 along positive z-axis
Answer: (a) 8 along negative x-axis
Question 16. Electric potential V due to an electric dipole is related to the distance r of the observation point as:
(a) V ∝ r
(b) V ∝ r-1
(c) V ∝ r²
(d) V ∝ r-2
Answer: (d) V ∝ r-2
Question 17. Equipotential surfaces
(a) are closer in regions of large electric fields compared to regions of lower electric fields.
(b) will be more crowded near sharp edges of a conductor.
(c) will always be equally spaced.
(d) both (a) and (b) are correct.
Answer: (d) both (a) and (b) are correct.
Question 18. Two capacitors of capacitance 6 µF and 4 µF are put in series across a 120 V battery. What is the potential difference across the 4 µF capacitor ?
(a) 72 V
(b) 60 V
(c) 48 V
Answer: (a) 72 V
Question 19. If a unit positive charge is taken from one point to another over an equipotential surface, then
(a) work is done on the charge.
(b) work is done by the charge.
(c) work done is constant.
(d) no work is done.
Answer: (d) no work is done
Question 20. Two insulated charged spheres of radii 20 cm and 25 cm respectively and having an equal charge q are connected by a copper wire and then they are separated.
(a) Both spheres will have the same charge q.
(b) Charge on sphere of radius 20 cm will be more than that of radius 25 cm.
(c) Charge on sphere of radius 20 cm will be lesser than that of 25 cm.
(d) Charge on each will be zq.
Answer: (c) Charge on sphere of radius 20 cm will be lesser than that of 25 cm