The deflection in a moving coil galvanometer falls from 50 divisions to 10 divisions,when a shunt of 20Ω is connected with it. The resistance of galvanometer coil is

Question

The deflection in a moving coil galvanometer falls from 50 divisions to 10 divisions,when a shunt of 20Ω is connected with it. The resistance of galvanometer coil is <img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/physics/624ec9d7641b5175cd6e6dd5fb574657-.png" /> (A)  24Ω (B)  12Ω (C)  6Ω (D)  48Ω

Tardigrade Admin · Accepted Answer

Here let the value of current from one division be i A.
Thus the current through ammeter

I = 50 i

and through Galvanometer

I_{g} = 10 I

S = \frac{I g _{g}}{I - I _{g}} G

\Rightarrow G = \frac{I - I _{g}}{I _{g}} S

= \frac{50 i - 10 i}{10 i} \times 12Ω

= 4 \times 12Ω

= 48Ω

Q. The deflection in a moving coil galvanometer falls from 50 divisions to 10 divisions,when a shunt of $20Ω$ is connected with it. The resistance of galvanometer coil is

$24Ω$

$12Ω$

$6Ω$

$48Ω$

Here let the value of current from one division be i A.
Thus the current through ammeter $I = 50 i$ and through Galvanometer $I_{g} = 10 I$
$S = \frac{I g _{g}}{I - I _{g}} G$
$\Rightarrow G = \frac{I - I _{g}}{I _{g}} S$
$= \frac{50 i - 10 i}{10 i} \times 12Ω$
$= 4 \times 12Ω$
$= 48Ω$

Q. The deflection in a moving coil galvanometer falls from 50 divisions to 10 divisions,when a shunt of 20Ω is connected with it. The resistance of galvanometer coil is

24Ω

12Ω

6Ω

48Ω