Question

Calculate the magnetic force per unit length that will act on a wire which makes an angle of $45^\circ $ with the direction of a uniform magnetic field of $0.20 \, T$ and carries $10A$ of current.

• A. $2\sqrt{2} \, N \, m^{- 1}$
• B. $\frac{2}{\sqrt{} 2} \, N \, m^{- 1}$
• C. $\frac{\sqrt{} 2}{2} \, N \, m^{- 1}$
• D. $4\sqrt{2} \, N \, m^{- 1}$

Answer 1

Answer: (B)

$I=10 \, A,\theta =45^{o}, \, B=0.2 \, T$
$\therefore F=IlBsin \theta $
$\therefore \, \frac{F}{l}=IBsin 45^{o} =10\times 0.2\times \frac{1}{\sqrt{2}}=\frac{2}{\sqrt{2}}N \, m^{- 1}$