Question

In half deflection method, a high resistance box is connected in series with the battery so that

• A. the deflection of the galvanometer is brought within the scale.
• B. power losses are minimized.
• C. high resistance values are easily available.
• D. none of the above.

Answer 1

The correct option is A the deflection of the galvanometer is brought within the scale.

In a deflection method, a high resistance box is connected in series with the battery in order to bring the deflection of galvanometer within the scale.

Let $G$ is the resistance of a galvanometer which gives full-scale deflection when $I_g$ current passes through it and R is a high resistance connected in series with the galvanometer, so that galvanometer is converted into voltmeter of given range $V$ volt,

$V=I_g(R+G)$

$V/I_g=R+G$

$R=V/I_g-G$

hence, for conversion of galvanometer into a voltmeter of range V volt, a high resistance R is connected in series.