Question

In the experiment of half deflection method if R =20 $\Omega$ and S =12 $\Omega$ for half deflection then the G (galvanometer resistance) is

• A. $20\Omega$
• B. $30\Omega$
• C. $40\Omega$
• D. $25\Omega$

Answer 1

Answer: (B)

$30\Omega$

For half deflection of the galvanometer the resistance of it is $G=\frac{RS}{R-S}$

So if we put value of $R$ and $S$ in formula of $G$ we get $G$ $=\frac{20\times 12}{20-12}=240/8=30\Omega$

Hence $G=30\Omega$. option B is correct.