Question

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

• A. $100\text{mA}$
• B. $900\text{mA}$
• C. $1\text{A}$
• D. $1.1\text{A}$

Answer 1

The correct option is C $1\text{A}$

In parallel, current distributes in inverse ratio of resistance.
$\Rightarrow \frac{0.01}{I-0.01}=\frac{0.1}{9+0.9}$

Solving we get $I=1\text{A}$
Hence, the correct answer is (C).