Question

A neutron, a proton, an electron and an $\alpha -particle$ enter a region of uniform magnetic field with the same velocities. The magnetic field is perpendicular and directed into the plane of the paper. The tracks of the particles are labelled in the figure. The electron follows the track _____.

• A. $D$
• B. $B$
• C. $C$
• D. $A$

Answer 1

The correct option is A $D$

Force on charged particle in magnetic field is given by

$F=q(\overrightarrow{\vartheta }\ast \overrightarrow{B})$

neutron will pass undeviated force on +ve charge will act leftward initially and on -ve charge rightward and hence both D belongs to electron.