Question

A uniform conducting wire $ABC$ has a mass of $10gm$ . A current of $2A$ flows through it. The wire is kept in a uniform magnetic field $B=2T$ .
The acceleration of the wire will be

• A. Zero
• B. $12ms^{- 2}$ along $y$ -axis
• C. $1.2\times 10^{- 3}ms^{- 2}$ along $y$ -axis
• D. $0.6\times 10^{- 3}$ along $y$ -axis

Answer 1

Answer: (B)

$\left(\bar{F}\right)_{mag}=\hat{i}l\botB\left(\right.\hat{j}\left.\right)$
$=2\times 3\times 10^{- 2}\times 2$
$a=\frac{F_{mag}}{m}=\frac{12 \times 10^{- 2}}{10 - 10^{- 3}}=12ms^{- 1}\hat{j}$