Question

A current of $0.5A$ produces a deflection of ${60}^o$ in a tangent galvanometer. The current that produces a deflection of ${30}^o$ in the same galvanometer is :

• A. $0.25A$
• B. $\frac{0.5}{3}A$
• C. $\frac{0.5}{\sqrt{2}}A$
• D. $\frac{0.5}{\sqrt{3}}A$

Answer 1

Answer: (B)

$\frac{0.5}{3}A$

$B_4\tan \theta =\frac{{\mu }_{0}i}{2r}$
$\frac{\tan {\theta }_1}{\tan {\theta }_2}=\frac{i_1}{i_2}$

$\frac{\tan 60}{\tan 30}=\frac{0\cdot 5}{i_2}$

$i_2=\frac{0\cdot 5\times \frac{1}{\sqrt{3}}}{\sqrt{3}}$
$i_2=\frac{0\cdot 5}{3}A$