Q. When the light of frequency $2\nu_0$ (where $\nu_0$ is threshold frequency), is incident on a metal plate, the maximum velocity of electrons emitted is $v_1$. When the frequency of the incident radiation is increased to $5\nu_0$, the maximum velocity of electrons emitted from the same plate is $v_2$. The ratio of $v_1$ to $v_2$ is
A) 4 : 1
B) 1 : 4
C) 1 : 2
D) 2 : 1
Explanation
[Solution] $\frac{1}{2}mv_1^2 = h\nu_0$, $\frac{1}{2}mv_2^2 = 4h\nu_0$, so $v_1 : v_2 = 1 : 2$. Answer (3).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.