JEE Physics Electrostatic Potential and Capacitance MCQs Set A

Question. The potential at a point 0.1 m from an isolated point charge is + 100 volt. The nature of the point charge is
(a) Positive
(b) Negative
(c) Zero
(d) Either positive or zero

Answer: A

Question. The potential gradient is a
(a) Vector quantity
(b) Scalar quantity
(c) Conversion factor
(d) Constant

Answer: A

Question. If on the x-axis electric potential decreases uniformly from 60 V to 20 V between x = –2 m to x = +2 m, then the magnitude of electric field at the origin
(a) May be greater than 10 V/m
(b) Is 5 V/m
(c) Must be 10 V/m
(d) Is zero

Answer: A

Question. When a test charge is brought in from infinity along the perpendicular bisector of an electric dipole, the work done is
(a) Zero
(b) Negative
(c) Positive
(d) None of these

Answer: A

Question. The work done in moving an electric charge q in an electric field does not depend upon
(a) Mass of the particle
(b) Magnitude of charge
(c) Potential difference between two points
(d) All of these

Answer: A

Question. If 50 joule of work must be done to move an electric charge of 2 C from a point, where potential is –10 volt to another point, where potential is V volt, the value of V is
(a) + 15 V
(b) + 10 V
(c) – 15 V
(d) 5 V

Answer: D

Question. The electric potential at a distance of 3 m on the axis of a short dipole of dipole moment 4 × 10^–12 coulomb-meter is
(a) 4 mV
(b) 12 mV
(c) 27 mV
(d) 1.33 × 10^–3 V

Answer: A

Question. The electric potential in volts due to an electric dipole of dipole moment 2 × 10^–8 coulomb-metre at a distance of 3m on a line making an angle of 60° with the axis of the dipole is
(a) 10
(b) 20
(c) 40
(d) Zero

Answer: A

Question. Two electrons are moving towards each other, each with a velocity of 10⁶ m/s. What will be closest distance of approach between them?
(a) 2.53 × 10^–10 m
(b) 2.53 × 10^–6 m
(c) Zero
(d) 1.53 × 10^–8 m

Answer: A

Question. Three charges –q, Q and –q are placed respectively at equal distances on a straight line. If the potential energy of the system of three charges is zero, then what is the ratio of Q : q ?
(a) 1 : 4
(b) 1 : 3
(c) 1 : 2
(d) 1 : 1

Answer: A

Question. 1000 small water drops each of capacitance C join together to form one large spherical drop. The capacitance of bigger sphere is
(a) 10 C
(b) 100 C
(c) 1000 C
(d) C

Answer: D

Question. Two parallel plate capacitors have their plate areas 100 cm² and 500 cm² respectively. If they have the same charge and potential and the distance between the plates of the first capacitor is 0.5 mm, then the distance between the plates of the second capacitor is
(a) 0.25 cm
(b) 0.20 cm
(c) 0.15 cm
(d) 0.10 cm

Answer: A

Question. A battery does 200 J of work in charging a capacitor. The energy stored in the capacitor is
(a) 100 J
(b) 200 J
(c) 50 J
(d) 400 J

Answer: A