JEE Physics · 160 questions. Try each one, then check the answer and solution.
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Q1.AI-generated practiceSingle-correct MCQEasy
Two point charges repel each other with a force F. If each charge is doubled and the distance between them is halved, the new force is:
Q2.AI-generated practiceSingle-correct MCQEasy
Two point charges of +2 μC and +8 μC are placed 30 cm apart in air. Take 1/(4πε0) = 9 × 109 N m2 C-2. The magnitude of the force between them is:
Q3.AI-generated practiceSingle-correct MCQMedium
Three identical point charges +q are placed at the vertices of an equilateral triangle of side a. The magnitude of the net electrostatic force on any one charge is (k = 1/4πε0):
Q4.AI-generated practiceSingle-correct MCQMedium
Point charges +4 μC and +1 μC are fixed 30 cm apart. A third charge placed on the line joining them experiences no net force when it is at:
Q5.AI-generated practiceSingle-correct MCQMedium
Charges +q and −4q are fixed a distance d apart. A third charge is to be placed on the line joining them so that it experiences zero net force. It must be placed:
Q6.AI-generated practiceSingle-correct MCQMedium
Two identical small conducting spheres carry charges +6 μC and −2 μC and attract each other with force F when kept at separation r. They are touched together and put back at the same separation. The new force is:
Q7.AI-generated practiceSingle-correct MCQHard
Two identical small balls, each of mass 10 g, are suspended from the same point by insulating threads 50 cm long. When given equal charges, each thread makes 37° with the vertical in equilibrium. Take g = 10 m/s2, sin 37° = 0.6, tan 37° = 0.75 and 1/(4πε0) = 9 × 109 N m2 C-2. The charge on each ball is about:
Q8.AI-generated practiceSingle-correct MCQEasy
Two point charges exert a force F on each other in air. If the same charges at the same separation are immersed in a liquid of dielectric constant 4, the force becomes:
Q9.AI-generated practiceSingle-correct MCQMedium
A charge Q is divided into two parts q and (Q − q), which are then placed a fixed distance apart. The repulsive force between them is maximum when q equals:
Q10.AI-generated practiceSingle-correct MCQMedium
Four equal charges +q are placed at the corners of a square of side a. The magnitude of the net force on any one charge due to the other three is (k = 1/4πε0):
Q11.AI-generated practiceSingle-correct MCQHard
Charges q1 = +3 μC and q2 = −4 μC are fixed at (0, 0) and (0.3 m, 0) respectively. A charge q3 = +1 μC is placed at (0, 0.4 m). Take 1/(4πε0) = 9 × 109 N m2 C-2. The magnitude of the net force on q3 is about:
Q12.AI-generated practiceSingle-correct MCQEasy
The ratio of the electrostatic repulsion to the gravitational attraction between two electrons is about (e = 1.6 × 10-19 C, me = 9.1 × 10-31 kg, G = 6.67 × 10-11 N m2 kg-2, 1/(4πε0) = 9 × 109 N m2 C-2):
Q13.AI-generated practiceSingle-correct MCQMedium
Which of the following values cannot be the net charge on an isolated body? (e = 1.6 × 10-19 C)
Q14.AI-generated practiceSingle-correct MCQHard
Two equal charges +Q are fixed a distance d apart, and a charge q is placed at the midpoint of the line joining them. For the whole system of three charges to be in equilibrium, q must be:
Q15.AI-generated practiceNumerical valueEasy
Two point charges of 4 μC and 9 μC are placed 0.6 m apart in air. Take 1/(4πε0) = 9 × 109 N m2 C-2. If the force between them is x × 10-1 N, find x.
Q16.AI-generated practiceNumerical valueMedium
A neutral metal sphere is given a charge of +8 μC by removing electrons. If the number of electrons removed is n × 1013, find n. (e = 1.6 × 10-19 C)
Q17.AI-generated practiceNumerical valueMedium
Two identical small conducting spheres carry charges +5 μC and −1 μC. They are touched together and then placed 30 cm apart. Take 1/(4πε0) = 9 × 109 N m2 C-2. If the force between them is x × 10-1 N, find x.
Q18.AI-generated practiceNumerical valueHard
A charge of +2 μC is at the origin. A charge of +3 μC is at (0.3 m, 0) and a charge of −4 μC is at (0, 0.3 m). Take 1/(4πε0) = 9 × 109 N m2 C-2. If the magnitude of the net force on the charge at the origin is x × 10-1 N, find x.
Q19.AI-generated practiceAssertion–ReasonMedium
Assertion (A): The force between two point charges is unaffected by the presence of a third charge nearby. Reason (R): Electrostatic forces obey the principle of superposition.
Q20.AI-generated practiceAssertion–ReasonHard
Assertion (A): The force between two charges kept at a fixed separation is smaller in a dielectric medium than in vacuum. Reason (R): The magnitude of each charge decreases when the charges are placed in a medium.