Q134 / 150 · MHT CET 2026 (17 April Shift 2) · Physics
The current passing through the galvanometer is 4 % of the total current in the curcuit. If the resistance of the galvanometer is 'G', the shunt resistance 'S' connected across the galvanometer is
- A$25\,G$
- B$24\,G$
- Correct answerC$\dfrac{G}{24}$
- D$\dfrac{G}{25}$
Solution
Let the total current in the circuit be $I$.
The current passing through the galvanometer is $I_g = 4\% \text{ of } I = \dfrac{4}{100}I = \dfrac{I}{25}$.
Since the galvanometer and the shunt resistance are connected in parallel, the potential difference across them is the same.
$I_g G = (I - I_g) S$
Substituting the value of $I_g$:
$\left(\dfrac{I}{25}\right) G = \left(I - \dfrac{I}{25}\right) S$
$\dfrac{I}{25} G = \dfrac{24I}{25} S$
$G = 24 S$
$S = \dfrac{G}{24}$
Answer: $\dfrac{G}{24}$
The current passing through the galvanometer is $I_g = 4\% \text{ of } I = \dfrac{4}{100}I = \dfrac{I}{25}$.
Since the galvanometer and the shunt resistance are connected in parallel, the potential difference across them is the same.
$I_g G = (I - I_g) S$
Substituting the value of $I_g$:
$\left(\dfrac{I}{25}\right) G = \left(I - \dfrac{I}{25}\right) S$
$\dfrac{I}{25} G = \dfrac{24I}{25} S$
$G = 24 S$
$S = \dfrac{G}{24}$
Answer: $\dfrac{G}{24}$
Hence, the correct answer is option: 'C'.