Question

A galvanometer has a coil of resistance $100$ and gives a full-scale deflection for $30mA$ current. It is to work as a voltmeter of $30$ Volt range, the resistance required to be added will be

• A. $900$
• B. $1800$
• C. $500$
• D. $2700$

Answer 1

Answer: (A)

$900$

A galvanometer has a coil of resistance 100 and gives a full-scale deflection for 30 mA current. It is to work as a voltmeter of 30 Volt range, the resistance required to be added will be

$R=\frac{V}{i_g}-G$

$R=\frac{30}{30\times {10}^{-3}}-100=900$