Question

What shunt resistance must be connected across a Galvanometer of 20 Ω resistance which gives full scale deflection with 2.0 A current, so as to convert it into an Ammeter of range 10 A?

Options

A
5 Ω
B
2 Ω
C
3 Ω
D
4 Ω

Explanation

Explanation:

Galvanometer resistance = G = 20Ω

Current = I1 = 10A

Current = I2 = 2 A

Shunt resistance = Rs = ?

So,

n = I1 / I2

n = 10 / 2

= 5

Applying the formula:

Rs = G / n - 1

= 20 / 5 - 1

= 20 / 4

Rs = 5 ohms

This is the correct answer. The shunt resistance is calculated using the formula R_s = G / (n - 1), where n = I₁ / I₂. Substituting the given values, we find that R_s = 5 Ω.

This is incorrect. Using a shunt resistance of 2 Ω would not provide the desired ammeter range of 10 A. Double-check your calculations using the correct formula.

This is incorrect. A shunt resistance of 3 Ω is too low to achieve the required range conversion. Ensure you are using the correct formula and values.

This is incorrect. Using a shunt resistance of 4 Ω would not convert the galvanometer to the desired range of 10 A. Verify your calculations.