Question

A proton enters a magnetic field of flux density 5 T with a velocity of 5 × 10^7 ms^-1 at an angle of 30^o with the field. Find the force on the proton.

(a) 0.2 × 10^-11 N

(b) 2 × 10^-11 N

(c) 20 × 10^-11 N

(d) 200 × 10^-11 N

The question was posed to me in class test.

I want to ask this question from Motion in a Magnetic Field topic in section Moving Charges and Magnetism of Physics – Class 12

Answer 1

Correct answer is (b) 2 × 10^-11 N

For explanation I would say: F = qvB sinθ.

F = 1.6 × 10^-19 × 5 × 10^7 × 5 × sin30^o

F = 2 × 10^-11 N.