Question

Assertion (A): The work done, in taking a unit charge around a closed loop of an electric circuit involving cells and resistors in the loop, is zero.

Reason (R): The potential at a point depends on the location of the point in the loop. After completing one round, the charge comes back to the point of start.

विकल्प

• Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).

• Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).

• Assertion (A) is true, but Reason (R) is false.

• Both Assertion (A) and Reason (R) are false.

Answer 1

Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).

Explanation:

Kirchhoff’s Loop Rule (KVL), which states that energy in an electric circuit is conserved, is related to this subject.

Kirchhoff’s loop law states that the algebraic total of potential changes around any closed loop equals zero, proving that assertion (A) is true. This suggests that a unit charge traveling around a closed loop has zero net work from electrostatic and non-electrostatic forces.

Since electric potential is a state function, Reason (R) is true. Only your position determines this. The final potential remains V even if a charge begins at a position with potential V and returns to that same spot.

The change in potential (∆V) = `V_"final" - V_"initial"`

= V − V

= 0

Since potential difference is defined as work done per unit charge, ∆V = 0 directly explains why the work done around a closed loop is zero.

∴ Both A and R are true, and R is the correct explanation of A.