Target Exam

CUET

Subject

Physics

Chapter

Current Electricity

Question:

In a galvanometer, there is a deflection of 10 divisions per mA. The resistance of the galvanometer is 60 Ω. If a shunt of 1 Ω is connected to the galvanometer and there are 100 divisions in all, on the scale of the galvanometer, the maximum current that this galvanometer can read is

Options:

600 mA

610 mA

10 mA

100 mA

Correct Answer:

610 mA

Explanation:

The correct answer is Option (2) → 610 mA

Given:

Deflection sensitivity: 10 divisions/mA → Current per division $i_d = 0.1$ mA

Galvanometer resistance: $R_g = 60$ Ω

Shunt resistance: $R_s = 1$ Ω

Total divisions: 100

Maximum galvanometer current: $I_g^\text{max} = i_d \times 100 = 0.1 \times 100 = 10$ mA

Maximum current through galvanometer with shunt: $I_\text{max} = I_g^\text{max} \left(1 + \frac{R_g}{R_s}\right)$

$I_\text{max} = 10 \text{ mA} \left(1 + \frac{60}{1}\right) = 10 \text{ mA} \times 61 = 610$ mA

Answer: $I_\text{max} = 610$ mA