Question

A galvanometer of resistance 20 Ω shown deflection of 10 divisions, when a current of 1 mA is passed through it. If a shunt of 4 Ω is connected and there are 50 divisions on the scale, the range of the galvanometer is ______.

Options

• 1 A

• 3 A

• 30 mA

• 11 mA

Answer 1

A galvanometer of resistance 20 Ω shown deflection of 10 divisions, when a current of 1 mA is passed through it. If a shunt of 4 Ω is connected and there are 50 divisions on the scale, the range of the galvanometer is 30 mA.

Explanation:

Current for 50 divisions,

I_g = `(1xx50)/10` = 5 mA

∴ `"I"_"g"/"I"="S"/("S"+"G")`

⇒ I = `(("S"+"G")/"S")` I_g

or I = `((4+20)/4)` 5mA

= 30 mA