Question

A milliammeter of range 10 mA and resistance 9 $\omega$ is joined in a circuit as shown in figure. The meter gives full-scale deflection for current I when A and B are used as its terminals. If current enters at A and leaves at B (C is left isolated), the value of I is

• A. 100 mA
• B. 900 mA
• C. 1 A
• D. 1.1 A

Answer 1

The correct option is C 1 A

$i_g=10mA=0.01A$

$V_A-V_B=(I-i_g)0.1=i_g(9+0.9)$

or $I=\frac{10\times 0.01}{0.1}=1A$