Question

Two tangent galvanometers $A$ and $B$ are identical except in their number of turns. They are connected in series. On passing a current through them, deflections of $60^\circ$ and $30^\circ$ are produced. The ratio of the number of turns in $A$ and $B$ is

• A. $1 : 3$
• B. $3 : 1$
• C. $1 : 2$
• D. $2 : 1$

Answer 1

Answer: (B)

As the current and the other factors are same for both the galvanometers
$N \propto \tan \theta$
$\frac{N_{1}}{N_{2}}=\frac{\tan 60^{\circ}}{\tan 30^{\circ}}$
$=\frac{\sqrt{3}}{1 / \sqrt{3}}$
$\Rightarrow \,\,\,\,\frac{N_{1}}{N_{2}}=3$