Question 365: Current Electricity

Question

A galvanometer having a resistance of 20 $$\Omega $$ and 30 divisions on both sides has figure of merit 0.005 ampere/division. The resistance that should be connected in series such that it can be used as a voltmeter upto 15 volt, is:

Accepted Answer

R
g
= 20$$\Omega $$
N
L
= N
R
= N = 30
FOM = $${1 \over \phi }$$ = 0.005 A/Div.
Current sentivity = CS = $$\left( {{1 \over {0.005}}} ight)$$ = $${\phi  \over {m I}}$$
$${m I}$$g
max
= 0.005 $$ 	imes $$ 30
= 15 $$ 	imes $$ 10
$$-$$2
= 0.15
15 = 0.15 [20 + R]
100 = 20 + R
R = 80

Answer

120 $$\Omega $$

Answer

125 $$\Omega $$

Answer

80 $$\Omega $$

Answer

100 $$\Omega $$

Current Electricity

A galvanometer having a resistance of 20 $\Omega $ and 30 divisions on both sides has figure of merit 0.005 ampere/division. The resistance that should be connected in series such that it can be used as a voltmeter upto 15 volt, is:

Choose the correct answer: