# Class 12 Physics Moving Charges and Magnetism: NCERT Solutions for Question 27

This page focuses on the detailed Moving Charges and Magnetism question answers for Class 12 Physics Moving Charges and Magnetism, addressing the question: 'A galvanometer coil has a resistance of 12 Ω and the metre shows full scale deflection for a current of 3 mA. How will you convert the metre into a voltmeter of range 0 to 18 V?'. The solution provides a thorough breakdown of the question, highlighting key concepts and approaches to arrive at the correct answer. This easy-to-understand explanation will help students develop better problem-solving skills, reinforcing their understanding of the chapter and aiding in exam preparation.
Question 27

## A galvanometer coil has a resistance of 12 Ω and the metre shows full scale deflection for a current of 3 mA. How will you convert the metre into a voltmeter of range 0 to 18 V?

Resistance of the galvanometer coil, G = 12 Ω

Current for which there is full scale deflection,  I= 3 mA = 3 × 10-3 A

Range of the voltmeter is 0, which needs to be converted to 18 V.

therefore, V = 18 V

Let a resistor of resistance R be connected in series with the galvanometer to convert it into a voltmeter. This resistance is given as:

Hence, a resistor of resistance 5998 Ω is to be connected in series with the galvanometer.