JEE Advanced 2014 · Paper 1 · Physics Q16

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PhysicsInteger+3Question 16 of 60

A galvanometer gives full scale deflection with 0.006 A current. By connecting it to a 4990 Ω resistance, it can be converted into a voltmeter of range 0-30 V. If connected to a $\dfrac{2n}{249}\ \Omega$ resistance, it becomes an ammeter of range 0-1.5 A. The value of $n$ is

Your answer

Answer and worked solution

Official answer: 5

Galvanometer resistance. As a voltmeter, $0.006(G+4990)=30$ , so $G=10\ \Omega$ .

Shunt for 1.5 A.
$S=\frac{I_gG}{I-I_g}=\frac{0.006\times10}{1.494}=\frac{10}{249}\ \Omega.$

Match. $\dfrac{2n}{249}=\dfrac{10}{249}$ , so $n=5$ .

Answer: 5

Topics:Ammeters and voltmeters Moving coil galvanometer

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JEE Advanced 2014 · Paper 1, Physics question 16