Question

Assertion (A): Superconductors are not in common use.

Reason (R): Mercury below 4.2 K is a superconductor. It is a very difficult to achieve such a low 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 and Reason (R) is the correct explanation of Assertion (A).

Explanation:

Superconductors are not in common use because they work only at extremely low temperatures. Mercury becomes a superconductor below 4.2 K, and maintaining such a low temperature is very difficult and expensive. Thus, the reason correctly explains the assertion.