Question

In the given potentiometer circuit internal resistance
r of the cell of emf E is to be determined. When key
K is open, balance length is 30 cm and when it is
closed, balance length is 25 cm. The value of ris
pour
R = 102
(1) 22
(3) 32
(2) 1.522
(4) 1.252​

Answer 1

(1)22 is the answer for ur easy question

Explanation:

use the formula,

$r =r 1( \frac{l1}{l2} - 1)$