A galvanometer has an internal resistance of 200 $\Omega$ and requires a current of 5.0 mA for full-scale deflection.What resistance should be connected in series with this galvanometer to make a voltmeter that reads 25 V at full-scale deflection?
A)2.4 k$\Omega$
B)4.8 k$\Omega$
C)5.0 k$\Omega$
D)5.2 k$\Omega$
E)9.6 k$\Omega$

Question

Quizplus · Accepted Answer

The resistance that needs to be added in series with the galvanometer to create a voltmeter can be calculated using the formula:

R = (V/I) - r

where:
V = full-scale voltage = 25 V
I = full-scale current = 5.0 mA = 0.005 A
r = internal resistance of galvanometer = 200 Ω

Substituting the given values we get:

R = (25/0.005) - 200
R = 5000 - 200
R = 4800 Ω

Therefore, the best choice is B) 4.8 kΩ.

A Galvanometer Has an Internal Resistance of 200 Ω\OmegaΩ And Requires a Current of 5

A Galvanometer Has an Internal Resistance of 200 $\Omega$ And Requires a Current of 5