Question

Consider a beam of electrons moving perpendicular to a uniform magnetic field of 10 Tesla as shown in the figure. The beam carries a current of ${10}^{-5}$ amp. The force on 1 m length of beam is :

• A. ${10}^{-5}N$
• B. ${10}^{-6}N$
• C. ${10}^{-3}N$
• D. ${10}^{-4}N$

Answer 1

The correct option is D ${10}^{-4}N$

$F=ilB$ since both $l$ and $B$ are perpendicular to each other.
$\therefore F={10}^{-5}\times 1\times 10N={10}^{-4}N$