JEE Physics Electrostatic Potential and Capacitance MCQs Set C

Question:

• a) 3 × 10^–2 C
• b) 2 × 10^–2 C
• c) 4 × 10^–2 C
• d) 1 × 10^–2 C

Answer: 3 × 10^–2 C

Question:

• a)

  

• b)

  

• c)

  

• d) 0

Answer:

Question: A parallel plate condenser has a uniform electric field E (V/m) in the space between the plates. If the distance between the plates is d (m) and area of each plate is A (m²) the energy (joules) stored in the condenser is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

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: 8 along negative X-axis

Question:

• a) Zero
• b)

  

• c)

  

• d)

  

Answer: Zero

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: The electric dipole potential varies as 1/r at large distance

Question:

• a) 9090
• b) 909
• c) 900
• d) 990

Answer: 9090

Question: The energy required to charge a parallel plate condenser of plate separation d and plate area of cross-section A such that the uniform electric field between the plates is E, is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: The electric potential at a point in free space due to a charge Q coulomb is Q × 10¹¹ volts. The electric field at that point is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

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: 80 V

Question:

• a) Zero 
• b) Infinite
• c)

  

• d)

  

Answer: Zero

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: There is an electric field E in x-direction. If the work done on moving a charge of 0.2 C through a distance of 2 m along a line making an angle 60° with x-axis is 4 J, then what is the value of E?

• a) 20 N/C
• b) 5 N/C
• c) 4 N/C
• d) 

  

Answer:  20 N/C

Question:

• a) 2 × 10^–2 C
• b) 1 × 10^–2 C
• c) 6 × 10^–2 C
• d) 5 × 10^–2 C

Answer: 2 × 10^–2 C

Question: The energy stored in a capacitor of capacity C and potential V is given by

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: An electron of mass m and charge e is accelerated from rest through a potential difference V in vacuum. Its final velocity will be

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

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: 1 eV 

Question: A parallel plate condenser with oil between the plates (dielectric constant of oil K = 2) has a capacitance C. If the oil is removed, then capacitance of the capacitor becomes

• a)

  

• b)

  

• c)

  

• d) 2C

Answer:

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: Increases

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

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: U/4

Question: Energy per unit volume for a capacitor having area A and separation d kept at potential difference V is given by

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

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: Remain same throughout the conductor

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) Connecting two in series and one in parallel
• b) Connecting all of them in series
• c) Connecting them in parallel
• d) Connecting two in parallel and one in series

Answer: Connecting two in series and one in parallel

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: Zero and minimum

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: 50 kV

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) Zero
• b)

  

• c)

  

• d)

  

Answer: Zero

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Identical charges (–q) are placed at each corners of cube of side b then electrostatic potential energy of charge (+q) which is placed at centre of cube will be

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

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: Increases

Question:

• a) pE
• b) pE/2
• c) 2pE
• d)

  

Answer: pE

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d) None of these

Answer:

Question: Three capacitors each of capacitance C and of breakdown voltage V are joined in series. The capacitance and breakdown voltage of the combination will be

• a)

  

• b)

  

• c)

  

• d) 3C, 3V

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

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: 5 × 10⁷

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

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: Decrease

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: A conducting sphere of radius R is given a charge Q. The electric potential and the electric field at the centre of the sphere respectively are

• a)

  

• b)

  

• c)

  

• d) Both are zero

Answer:

Question:  In a region, the potential is represented by V(x, y, z) = 6x – 8xy – 8y + 6yz, where V is in volts and x, y, z are in metres. The electric force experienced by a charge of 2 coulomb situated at point (1, 1, 1) is

• a)

  

• b)

  

• c) 30 N
• d) 24 N

Answer: