Current Electricity Ques 87 — JEE PYQ Chapterwise

Answer:

Correct Answer: 87.(d)

Solution:

87. With increase in temperature, the value of unknown resistance will increase.

In balanced Wheat stone bridge condition,

$ \frac{R}{X}=\frac{l _1}{l _2} $

Here, $R=$ value of standard resistance.

$ X=\text { value of unknown resistance. } $

To take null point at same point

or $\frac{l _1}{l _2}$ to remain unchanged, $\frac{R}{X}$ should also remain unchanged.

Therefore, if $X$ is increasing $R$, should also increase.

$\therefore$ Correct option is $(d)$.