If the galvanometer G does not show any deflection in the circuit shown, the value of R is given by:

If the galvanometer $G$ does not show any deflection in the circuit shown, the value of $R$ is given by:

A $400\ \Omega$

B $200\ \Omega$

C $50\ \Omega$

D $100\ \Omega$

The answer is D.

Solution

No current in $G$ means the potential difference across $R$ is 2 V; $R=100\ \Omega$.

No current through 'G', so the potential difference across R is 2 V. $i=\frac{8}{400}$ $R=\left(\frac{2}{8}\times400\right)=100\ \Omega$

Concept null deflection in galvanometer

130 questions from this chapter have appeared across 27 exam years.