Question 489: Current Electricity

Question

With a resistance ' X ' connected in series with a galvanometer of resistance $100 \Omega$, it acts as a voltmeter of range $0-15 \mathrm{~V}$. To double the range, a resistance of $1500 \Omega$ is to be connected in series with ' X '. The value of ' X ' in ohm is

Accepted Answer

When the $150 \Omega$ resistor is connected,
$$ \Rightarrow \quad I_1=\frac{15}{100+X} $$
Given, when $1500 \Omega$ resistor is connected the range is doubled.
$$ \begin{array}{ll} \Rightarrow \quad & I_2=\frac{(2 	imes 15)}{1600+X} \ & 	ext { Also, } I_1=I_2 \ \Rightarrow \quad & \frac{15}{150+X}=\frac{30}{1650+X} \ & \frac{15(1600+X)}{30}=100+X \ & 1600+X=200+2 X \ 	herefore \quad & R=1400 \Omega \end{array} $$

Answer

900

Answer

1100

Answer

1400

Answer

1600

Current Electricity

With a resistance ' X ' connected in series with a galvanometer of resistance 100 \Omega, it acts as a voltmeter of range 0-15 \mathrm{~V}. To double the range, a resistance of 1500 \Omega is to be connected in series with ' X '. The value of ' X ' in ohm is

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