Question

Assertion $(A)$ In a meter bridge experiment, null point for an unknown resistance is put inside an enclosure maintained at a higher temperature. The null point can be obtained at the same point as before by decreasing the value of the standard resistance.
Reason $(R)$ Resistance of metal increases with increase in temperature.

• A. If both Assertion and Reason are true and Reason is correct explanation of Assertion.
• B. If both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
• C. If Assertion is true but Reason is false.
• D. If both Assertion and Reason are false.

Answer 1

Answer: (D)

As there is an increase in temperature, then the value of unknown resistance will increase.
In balanced condition, (referred Wheatstone bridge)
$\frac{R}{X}=\frac{l_{1}}{l_{2}}$
where, $R=$ standard (known resistance)
$X=$ unknown resistance.