A galvanometer having a coil resistance 100 Ω gives a full scale deflection when a current of 1 mA is passed through it. What is the value of the resistance which can convert this galvanometer into a voltmeter giving full scale deflection for a potential difference of 10 V ?

Question

A galvanometer having a coil resistance 100 Ω gives a full scale deflection when a current of 1 mA is passed through it. What is the value of the resistance which can convert this galvanometer into a voltmeter giving full scale deflection for a potential difference of 10 V ? (A) 3.9 kΩ (B) 10 kΩ (C) 9.9 kΩ (D) 7.9 kΩ

Tardigrade Admin · Accepted Answer

ig=1 mA, Rg=100 Ω V=ig(R+Rg) 10=1×10-3(R+100) R=9.9 kΩ

Q. A galvanometer having a coil resistance $100 Ω$ gives a full scale deflection when a current of 1 mA is passed through it. What is the value of the resistance which can convert this galvanometer into a voltmeter giving full scale deflection for a potential difference of 10 V ?

$3.9 k Ω$

$10 k Ω$

$9.9 k Ω$

$7.9 k Ω$

$i_{g} = 1 m A, R_{g} = 100 Ω$
$V = i_{g} (R + R_{g})$
$10 = 1 \times 1 0^{- 3} (R + 100)$
$R = 9.9 k Ω$

Q. A galvanometer having a coil resistance 100Ω gives a full scale deflection when a current of 1 mA is passed through it. What is the value of the resistance which can convert this galvanometer into a voltmeter giving full scale deflection for a potential difference of 10 V ?

3.9kΩ

10kΩ

9.9kΩ

7.9kΩ