1. Tardigrade
  2. Question
  3. Physics
  4. In the circuit, the galvanometer G shows zero deflection. If the batteries A and B have negligible internal resistance, the value of the resistor R will be :

Question Error Report

Thank you for reporting, we will resolve it shortly

Back to Question

Q. In the circuit, the galvanometer $G$ shows zero deflection. If the batteries $A$ and $B$ have negligible internal resistance, the value of the resistor $R$ will be :Physics Question Image

AIEEEAIEEE 2005Moving Charges and Magnetism

Solution:

The galvanometer shows zero deflection, i.e., current through $XY$ is zero
As a result potential drop across $R$ is $2\, V$ circuit can be redrawn as
$I=\frac{12}{500+R}$
Voltage across $R, V = IR$
$\Rightarrow 2=\frac{12}{500+R}\times R$
$\Rightarrow 1000 + 2R = 12R \Rightarrow R=100\,\Omega$

Solution Image Solution Image