If resistance of voltmeter is 10000 Ω and resistance of galvanometer is 2 Ω , then find R when voltmeter reads 12 V and galvanometer reads 0.1 A.

Question

If resistance of voltmeter is 10000 Ω and resistance of galvanometer is 2 Ω , then find R when voltmeter reads 12 V and galvanometer reads 0.1 A. (A)  118 Ω  (B)  120 Ω  (C)  124 Ω  (D)  114 Ω

Tardigrade Admin · Accepted Answer

The circuit diagram with current variation can be drawn as:

Let current

I_{g}

flows through R and G.
For a voltmeter with full scale reading, we have

V = I_{g} (G + R)

or

R = \frac{V}{I _{g}} - G

Given,

G = 2Ω, V = 12 v o lt, I_{g} = 0.1 A

∴

R = \frac{12}{0.1} - 2

= 120 - 2

= 118 Ω

Q. If resistance of voltmeter is $10000 Ω$ and resistance of galvanometer is $2 Ω,$ then find R when voltmeter reads 12 V and galvanometer reads 0.1 A.

$118 Ω$

$120 Ω$

$124 Ω$

$114 Ω$

Q. If resistance of voltmeter is 10000Ω and resistance of galvanometer is 2Ω, then find R when voltmeter reads 12 V and galvanometer reads 0.1 A.

118Ω

120Ω

124Ω

114Ω

The circuit diagram with current variation can be drawn as: Let current Ig​ flows through R and G. For a voltmeter with full scale reading, we have V=Ig​(G+R) or R=Ig​V​−G Given, G=2Ω,V=12volt,Ig​=0.1A ∴ R=0.112​−2 =120−2 =118Ω

Q. If resistance of voltmeter is $10000 Ω$ and resistance of galvanometer is $2 Ω,$ then find R when voltmeter reads 12 V and galvanometer reads 0.1 A.

$118 Ω$

$120 Ω$

$124 Ω$

$114 Ω$