Physics · Electrostatics · chapter 1 of 14

Class 12 Physics Chapter 1: Electric Charges and Fields Assertion-reason questions with answers

2 assertion-reason questions on Electric Charges and Fields, each with its answer and the reason, written from the NCERT chapter. For the CBSE board, JEE Main and NEET, which are set from the same NCERT chapter. Open a question's solution to check your working; then take the free test to find your next chapter. Each question gives an Assertion (A) and a Reason (R); choose how they stand to each other.

Question 1
Assertion (A): A metal spoon held in the hand shows no charge after it is rubbed with wool. Reason (R): Charge placed on a metal stays where it is put and does not move.
Show answer

Answer: (c) A is true, but R is false.

A is true: the charge leaks through the body to the ground. R is false: in a conductor the electrons are comparatively free to move, and charge placed on it spreads over its surface; it is on an insulator that charge stays put.

Question 2
Assertion (A): A small oil drop can carry a charge of 2.4 × 10⁻¹⁹ C (take e = 1.6 × 10⁻¹⁹ C). Reason (R): Every free charge is an integral multiple of the basic unit e.
Show answer

Answer: (d) A is false, but R is true.

R is true: charge is quantised, q = ne. A is false, because 2.4 × 10⁻¹⁹ C is 1.5e, not a whole-number multiple of e.

Take the free Class 12 Physics testSee the Class 12 flashcards

Chapter 2: Electrostatic Potential and Capacitance →