Question

) Write the expression for the magnetic force acting on a charged particle moving with

velocity in the presence of magnetic field B.

(ii) A neutron, an electron and an alpha particle moving with equal velocities, enter a

uniform magnetic field going into the plane of the paper as shown in the figure. Trace

their paths in the field and justify your answer. ​

Answer 1

Explanation:

(A) We know that,

F=qVB

Where, F= force,q= charge,V= velocity and B= magnetic field and

F=

r

mV

2

; m=mass, V= velocity, r= radius.

∴

r

mV

2

=qVB

(B)For electron q=-ve and m=me

Thus circular path.

For alpha, q= +ve, m=mp

Thus circular and larger radii, but neutron has q=0, thus continue in initial velocity.

Force on alpha particle and electron are opposite to each other, magnitude of

charge of alpha particle is more than electron hence radius of alpha particle is more

than radius of electron.