Question

Assertion :A potentiometer is a three-terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider.If only two terminals are used, one end and the wiper, it acts as a variable resistor or rheostat. Reason: Sometimes a rheostat is made from resistance wire wound on a heat-resisting cylinder, with the slider made from a number of metal fingers

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is B Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

Here $B$ is dividing voltage between $A$ and $C$.

And if we use $A$ and $B$ it will work as variable resistor as resistance is changing with movement of $B$.

In Reason, there is one type of rheostat is discussed, it is not explaining working of rheostat required in the given Assertion.

So option B is correct.