A galvanometer having a coil resistance of 100 Ω gives a full scale deflection, when a current of 1 mA is passed through it. The value of the resistance, which can convert this galvanometer into ammeter giving a full scale deflection for a current of 10 A is :

Question

A galvanometer having a coil resistance of 100 Ω gives a full scale deflection, when a current of 1 mA is passed through it. The value of the resistance, which can convert this galvanometer into ammeter giving a full scale deflection for a current of 10 A is : (A) 0.01 Ω (B) 2 Ω (C) 0.1 Ω (D) 3 Ω

Tardigrade Admin · Accepted Answer

Maximum voltage that can be applied across the galvanometer coil = 100 Ω × 10-3 A = 0.1 V. If Rs is the shunt resistance: RS × 10 A = 0.1 V ⇒ RS = 0.01 Ω

Q. A galvanometer having a coil resistance of $100 Ω$ gives a full scale deflection, when a current of $1 m A$ is passed through it. The value of the resistance, which can convert this galvanometer into ammeter giving a full scale deflection for a current of $10 A$ is :

$0.01 Ω$

$2 Ω$

$0.1 Ω$

$3 Ω$

Maximum voltage that can be applied across the galvanometer coil $= 100 Ω \times 1 0^{- 3} A = 0.1 V .$
If $R_{s}$ is the shunt resistance :
$R_{S} \times 10 A = 0.1 V$
$\Rightarrow R_{S} = 0.01Ω$

Q. A galvanometer having a coil resistance of 100Ω gives a full scale deflection, when a current of 1mA is passed through it. The value of the resistance, which can convert this galvanometer into ammeter giving a full scale deflection for a current of 10A is :

0.01Ω

2Ω

0.1Ω

3Ω