The figure shows a meter-bridge circuit where X=12 Ω and R=18 Ω. The jockey J is at the null point. If R is made 8 Ω, through what distance will the jockey J have to be moved to obtain null point again?

Question

The figure shows a meter-bridge circuit where X=12 Ω and R=18 Ω. The jockey J is at the null point. If R is made 8 Ω, through what distance will the jockey J have to be moved to obtain null point again? (A) 10 cm (B) 20 cm (C) 30 cm (D) 40 cm

Tardigrade Admin · Accepted Answer

(A J/100-A J)=(X/R)=(12/18) ⇒ A J=40 cm After changing R: (A J'/100-A J')=(12/8) ⇒ A J'=60 cm Shifting: A J'-A J=20 cm

Q. The figure shows a meter-bridge circuit where $X = 12 Ω$ and $R = 18 Ω$ . The jockey $J$ is at the null point. If $R$ is made $8 Ω$ , through what distance will the jockey $J$ have to be moved to obtain null point again?

10 cm

20 cm

30 cm

40 cm

$\frac{A J}{100 - A J} = \frac{X}{R} = \frac{12}{18}$
$\Rightarrow A J = 40 c m$
After changing $R$ :
$\frac{A J ^{'}}{100 - A J ^{'}} = \frac{12}{8}$
$\Rightarrow A J^{'} = 60 c m$
Shifting: $A J^{'} - A J = 20 c m$

Q. The figure shows a meter-bridge circuit where X=12Ω and R=18Ω. The jockey J is at the null point. If R is made 8Ω, through what distance will the jockey J have to be moved to obtain null point again?