Question

Assertion (A): The resistance offered by a unit cube [1 cm³ or 1 m³] such that current enters and leaves from its opposite ends is called specific resistance.

Reason (R): Specific resistance is a constant quantity at a given temperature.

Options

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

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

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

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

Answer 1

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

Explanation:

By definition, the resistance of a unit cube with current entering and leaving through opposite faces is called specific resistance or resistivity, so the assertion is true. At a given temperature, specific resistance is constant for a given material, so the reason is also true. But this constancy is a property of specific resistance; it does not explain its definition.