Question

A proton and an electron simultaneously enter into a region in which a uniform magnetic field acts normal to the motion of both the particles. The frequency of revolution of:

• A. the proton is greater than that of the electron
• B. the electron is greater than that of the proton
• C. the proton is equal to that of the electron
• D. both are having the same frequency, but revolve in opposite direction

Answer 1

Answer: (B)

the electron is greater than that of the proton

f = $\frac{QB}{2\pi m}=\left(\frac{QB}{2\pi }\right)\frac{1}{m}$
mass of electron < mass of proton
$f_e$ > $f_p$