Question

Assertion: The efficiency of a machine is always less than 100%.

Reason: This happens because practical mechanical advantage is always less than theoretical mechanical advantage due to friction and the weight of the moving parts.

Options

• If both Assertion and Reason are true and the Reason is correct explanation of the Assertion.

• If both Assertion and Reason are true, but Reason is not correct explanation of the Assertion.

• If Assertion is true, but the Reason is false.

• If Assertion is false, but the Reason is true.

Answer 1

If both Assertion and Reason are true and the Reason is correct explanation of the Assertion.

Explanation:

The efficiency of a practical machine is always less than 100% because some input energy is lost, mainly due to friction. Therefore, the Assertion (A) is true.

In a practical machine, the actual mechanical advantage is less than the ideal or theoretical mechanical advantage because of friction and the weight of moving parts. Therefore, the Reason (R) is true and correctly explains the Assertion.

Hence, both A and R are true and R is the correct explanation of A.