A potentiometer wire P Q of 1 m length is connected to a standard… - Vidyadip

MCQ

A potentiometer wire $P Q$ of $1 m$ length is connected to a standard cell $E_1$. Another cell $E_2$ of emf $1.02 V$ is connected with a resistance ' $r$ ' and switch $S$ (as shown in figure). With switch $S$ open, the null position is obtained at a distance of $49 cm$ from $Q$. The potential gradient in the potentiometer wire is

A
$0.03 V / cm$
✓
$0.02 V / cm$
C
$0.01 V / cm$
D
$0.04 V / cm$

✓

Answer

Correct option: B.

$0.02 V / cm$

(b) : Here $P Q=1 m , E_2=1.02 V$
When $S$ is open, $P J=P Q-J Q=100-49=51 cm$
Also, $E_2=k P J$
Potential gradient in the wire, $k=\frac{E_2}{P J}$
$
k=\frac{1.02 V }{51 cm }=0.02 V / cm
$

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