### JEE Main 12 Jan 2019 Evening Question 25

##### Question: A galvanometer, whose resistance is 50 ohm, has 25 divisions in it. When a current of $ 4\times {10^{-4}} $ A passes through it, its needle (pointer) deflects by one division. To use this galvanometer as a voltmeter of range 2.5 V, it should be connected to a resistance of [JEE Main Online Paper Held On 12-Jan-2019 Evening]

#### Options:

A) 200 ohm

B) 6250 ohm

C) 6200 ohm

D) 250 ohm

## Show Answer

#### Answer:

Correct Answer: A

#### Solution:

The full scale deflection current $ I _{g}=25\times 4\times {10^{-4}}A $

Let R be the resistance connected $ I _{g}=\frac{V}{R+R _{g}}\Rightarrow 25\times 4\times {10^{-4}}=\frac{2.5}{R+50} $

$ \Rightarrow $ $ R=200\Omega $