Question

Pls help me friends I really need your help with this piece of question

Answer 1

You must know this formula before solving this question,

F = q ( V x B)

where,
F = force of charged particle
q = charge of charged particle
V = velocity of charge particle
B = strength of Magnetic Field

And here this force will be balanced by Centrifugation force

Therefore

$\frac{ m {v}^{2} }{r} = q \: v \: B$

$B = \frac{m \: v}{q \: r}$

$B = \frac{(5 \times {10}^{ - 3})(5) }{(5 \times {10}^{ - 6})(5) }$

r = 5 m because radius of circle is 5.

B = 1000 Tesla
B = 1K Tesla

Option B.

Answer is Option B because direction of velocity and Magnetic Field will be perpendicular.