JEE Physics Electric Charges and Fields MCQs Set A

Question: If a body has positive charge on it, then it means it has

• a) Lost some electrons
• b) Lost some protons
• c) Process of induction
• d) Attraction between bodies

Answer: Lost some electrons

Question: Sure check for presence of electric charge is

• a) Repulsion between bodies
• b) Frictional force between bodies
• c) Process of induction
• d) Attraction between bodies

Answer: Repulsion between bodies

Question: If a solid and a hollow conducting sphere have same radius then

• a) Both the spheres will hold same maximum charge
• b) Solid sphere will hold more maximum charge
• c) Hollow sphere will hold more maximum charge
• d) Both the sphere can’t hold charge

Answer: Both the spheres will hold same maximum charge

Question: When a conducting soap bubble is negatively charged then

• a) It expands
• b) No change in its size takes place
• c) Its size starts varying arbitrarily
• d) It contracts

Answer: It expands

Question: Five balls marked a to e are suspended using separate threads. Pairs (b, c) and (d, e) show electrostatic repulsion while pairs (a, b), (c, e) and (a, e) show electrostatic attraction. The ball marked a must be

• a) Uncharged
• b) Negatively charged
• c) Positively charged
• d) Any of the above is possible

Answer: Uncharged

Question: When a plastic rod rubbed with wool is brought near the knob of a negatively charged gold leaf electroscope, the gold leaves

• a) Dilate
• b) Collapse completely
• c) Contract
• d) Start oscillating

Answer: Dilate

Question: Coulomb’s law is analogous to

• a) Newton’s law of gravitation
• b) Newton’s second law of motion
• c) Charge conservation law
• d) Law of conservation of energy

Answer: Newton’s law of gravitation

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Two equally charged identical small balls kept some fixed distance apart exert a repulsive force F on eachother. A similar uncharged ball, after touching one of them is placed at the mid-point of line joining the two balls. Force experienced by the third ball is

• a) F
• b) 2F
• c) 4F
• d)

  

Answer: F

Question:  Two equal point charges A and B are R distance apart. A third point charge placed on the perpendicular bisector at a distance ‘d’ from the centre will experience maximum electrostatic force when

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: A charged gold leaf electroscope has its leaves apart by certain amount having enclosed air. When the electroscope is subjected to X-rays, then the leaves

• a) Collapse
• b) Remain unaltered
• c) Start oscillating
• d) Further dilate

Answer: Collapse

Question: Two equal positive charges Q are fixed at points (a, 0) and (–a, 0) on the x-axis. An opposite charge –q at rest is released from point (0, a) on the y-axis. The charge –q will

• a) Execute oscillatory periodic motion but not SHM
• b) Move to origin and rest there
• c) Move to infinity
• d) Undergo SHM about the origin

Answer: Execute oscillatory periodic motion but not SHM

Question: Four charges each equal to Q are placed at the four corners of a square and a charge q is placed at the centre of the square. If the system is in equilibrium then the value of q is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Which of the following is not true about electric charge?

• a) Charge can be converted into energy and energy can be converted into charge
• b) Net charge on an isolated system is always conserved
• c) Charge is a scalar quantity
• d) Charge on a body is always integral multiple of certain charge known as charge of electron

Answer: Charge can be converted into energy and energy can be converted into charge

Question: What is the amount of charge possessed by 1 kg of electrons?

• a) 1.76 × 10¹¹ C
• b) 1.76 × 10^–9 C
• c) 1.76 × 10^–7 C
• d) 1.76 × 10^–5 C

Answer: 1.76 × 10¹¹ C

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:  A charge q is to be distributed on two conducting spheres. What should be the value of the charges on the spheres so that the repulsive force between them is maximum when they are placed at a fixed distance from each other in air?

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) Remains unchanged
• b) Increases
• c) Decreases
• d)

  

Answer: Remains unchanged

Question:

• a) –q
• b) 4q
• c)

  

• d)

  

Answer: –q

Question:

• a)

  

• b)

  

• c)

  

• d) Zero

Answer:

More Questions....................................................

Question: Consider three point objects P, Q and R. P and Q repel each other, while P and R attract. What is the nature of force between Q and R?

• a) Attractive force
• b) Repulsive force
• c) No force
• d) None of these

Answer: Attractive force

Question: Which of the following processes involves the principle of electrostatic induction?

• a) All of these
• b) Xerox copying
• c) Chocolate making
• d) Pollination

Answer: All of these

Question: The electric field intensity at a point in vacuum is equal to

• a) Force a unit positive charge would experience there
• b) Force an electron would experience there
• c) Force a proton would experience there
• d) Zero

Answer: Force a unit positive charge would experience there

Question: A sphere of radius r has electric charge uniformly distributed in its entire volume. At a distance d from the centre inside the sphere (d < r) the electric field intensity is directly proportional to

• a) d
• b) d²
• c)

  

• d)

  

Answer: d

Question:

• a) 2E
• b) Zero
• c) 4E
• d) 16E

Answer: 2E

Question: In a uniform electric field if a charge is fired in a direction different from the line of electric field then the trajectory of the charge will be a

• a) Parabola
• b) Ellipse
• c) Circle
• d) Straight line

Answer: Parabola

Question: A positively charged pendulum is oscillating in a uniform electric field pointing upwards. Its time period as compared to that when it oscillates without electric field

• a) Is more
• b) Is less
• c) Remains unchanged
• d) Starts fluctuating

Answer: Is more

Question: How many electrons should be removed from a coin of mas 1.6 g, so that it may float in an electric field of intensity 10⁹ N/C directed upward?

• a) 9.8 × 10⁷
• b) 9.8 × 10⁵
• c) 9.8 × 10³
• d) 9.8 × 10¹

Answer:  9.8 × 10⁷

Question:

• a) Zero
• b)

  

• c)

  

• d)

  

Answer: Zero

Question:

• a)

  

• b)

  

• c)

  

• d) 2

Answer:

Question:

• a) OB
• b) OD
• c) OE
• d) OC

Answer: OB

Question:  Two charges e and 3e are placed at a distance r. The distance of the point where the electric field intensity will be zero is

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a) Non-uniform
• b) Both uniform and non-uniform
• c) Uniform
• d) Zero everywhere

Answer: Non-uniform

Question: An uncharged sphere of metal is placed in a uniform electric field produced by two oppositely charged plates. The lines of force will appear as

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: An electron released on the axis of a positively charged ring at a large distance from the centre will

• a) Do oscillatory motion
• b) Do SHM
• c) Do non periodic motion
• d) Not move

Answer: Do oscillatory motion

Question: Electric charge Q, Q and –2Q respectively are placed at the three corners of an equilateral triangle of side a. Magnitude of the electric dipole moment of the system is

• a)

  

• b)

  

• c) Qa
• d) 2Qa

Answer:

Question: An electric dipole placed in a uniform electric field experiences maximum moment of couple when the dipole is placed

• a) Perpendicular to the direction of the field
• b) Against the direction of the field
• c) Towards the electric field
• d) At 135° to the direction of the field

Answer: Perpendicular to the direction of the field

Question: Force of interaction between two co-axial short electric dipoles whose centres are R distance apart varies as

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question:

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: The electric force on a point charge situated on the axis of a short dipole is F. If the charge is shifted along the axis to double the distance, the electric force acting will be

• a)

  

• b)

  

• c)

  

• d) 4F

Answer: