Question 159: Electromagnetic Induction

Question

A 1 m long metal rod XY completes the circuit as shown in figure. The plane of the circuit is perpendicular to the magnetic field of flux density 0.15 T. If the resistance of the circuit is 5$$\Omega$$, the force needed to move the rod in direction, as indicated, with a constant speed of 4 m/s will be ____________ 10$$^{-3}$$ N.

Accepted Answer

To move the rod with a constant velocity $v=4 \mathrm{~m} \mathrm{~s}^{-1}$
$\mathrm{F}_{	ext {net }}$ on the rod should be zero.
$$
\begin{aligned}
F & =B i l=0.15\left(\frac{B l v}{R}ight) l \\
& =0.15\left(\frac{0.15 	imes 1 	imes 4}{5}ight) 	imes 1 \\
& =0.03 	imes 0.15 	imes 4 \\
& =180 	imes 10^{-4} \mathrm{~N} \\
& =18 	imes 10^{-3} \mathrm{~N}
\end{aligned}
$$

Electromagnetic Induction

Integer / Numeric Answer Type