Question

A voltmeter reads 5.0 V at full scale deflection and is graded according to its resistance per volt at full scale
deflection as 2000 Q . How will you convert it into a voltmeter that reads 15 V at full scale deflection​

Answer 1

Answer:

A voltmeter reads 5.0 V at full scale deflection and is graded according to its resistance per volt at full scale

deflection as 2000 Q

Explanation:

The 5 V voltmeter is graded as 2000 Ω/V

its resistance must be = 5 × 2000 = 10000 Ω

ig = V/(R+G)

=> ig = 5/10000

=> ig = 0.0005 A

For 15 V voltmeter, let the resistance to be X.

ig = 15/x

=> x = 15/0.0005

=> x = 30000 Ω

Therefore for the conversion of the voltmeter from 5 V to 15 V the resistance to be added in series is = 30000 – 10000

= 20000 Ω