JEE Physics Electrostatic Potential and Capacitance MCQs Set C

Question. The electric potential V at any, point (x, y, z), in meters in space is given by V = 4x² volt. The electric field at the point (1, 0, 2) in volt/meter, is
(a) 8 along negative X-axis
(b) 16 along negative X-axis
(c) 16 along positive X-axis
(d) 8 along positive X-axis

Answer: A

Question. Which of the following is not true?
(a) The electric dipole potential varies as 1/r at large distance
(b) For a point charge, the electrostatic field varies as 1/r²
(c) For a dipole, the potential depends on the position vector and dipole moment vector
(d) For a point charge, the electrostatic potential varies as 1/r

Answer: A

Question. A hollow metallic sphere of radius 10 cm is charged such that potential of its surface is 80 V. The potential at the centre of the sphere would be
(a) 80 V
(b) 800 V
(c) Zero
(d) 8 V

Answer: A

Question. When a proton is accelerated through 1 V, then its kinetic energy will be
(a) 1 eV
(b) 13.6 eV
(c) 1840 eV
(d) 0.54 eV 

Answer: A

Question. In bringing an electron towards another electron, the electrostatic potential energy of the system
(a) Increases
(b) Decreases
(c) Remains same
(d) Becomes zero

Answer: A

Question. A capacitor is charged with a battery and energy stored is U. After disconnecting battery another capacitor of same capacity is connected in parallel to the first capacitor. Then energy stored in each capacitor is
(a) U/4
(b) 4U
(c) 2U
(d) U/2

Answer: A

Question. Some charge is being given to a conductor. Then its potential is
(a) Remain same throughout the conductor
(b) Maximum somewhere between surface and centre
(c) Maximum at centre
(d) Maximum at surface

Answer: A

Question. An electric dipole has the magnitude of its charge as q and its dipole moment is p. It is placed in a uniform electric field E. If its dipole moment is along the direction of the field, the force on it and its potential energy are respectively
(a) Zero and minimum
(b) qE and maximum
(c) qE and pE
(d) 2qE and minimum

Answer: A

Question. A bullet of mass 2 kg is having a charge of 2 mC. Through what potential difference must it be accelerated, starting from rest, to acquire a speed of 10 m/s?
(a) 50 kV
(b) 5 kV
(c) 50 V
(d) 5 V

Answer: A

Question. A parallel plate air capacitor is charged to a potential difference of V volts. After disconnecting the charging battery the distance between the plates of the capacitor is increased using an insulating handle. As a result the potential difference between the plates
(a) Increases
(b) Decreases
(c) Does not change
(d) Becomes zero

Answer: A

Question. The mean free path of electrons in a metal is 4 × 10^–8 m. The electric field which can give on an average 2 eV energy to an electron in the metal will be in units of V/m
(a) 5 × 10⁷
(b) 8 × 10⁷
(c) 9 × 10⁷
(d) 1 × 10⁷

Answer: A

Question. Two parallel metal plates having charges +Q and –Q face each other at a certain distance between them. If the plates are now dipped in kerosene oil tank, the electric field between the plates will
(a) Decrease
(b) Remain same
(c) Increase
(d) Become zero

Answer: A