Which of the following is not true about the stopping potential in th…

The correct answer is Option (2) → Stopping potential is same for incident radiation of different frequencies.

By Einstein’s photoelectric equation, the stopping potential satisfies \( eV_0 = h\nu - \phi_0 \): it depends on the frequency of the light and on the work function of the material.

Option (1) Stopping potential is a negative retarding potential — True. The collector is made negative with respect to the emitter; this retarding potential stops even the fastest photoelectrons.

Option (2) Stopping potential is same for incident radiation of different frequencies. — Not true. \( V_0 = (h\nu - \phi_0)/e \) increases linearly with the frequency, so it is different for different frequencies.

Option (3) Stopping potential is different for different materials — True. For the same frequency, a metal with a larger work function has a smaller stopping potential.

Option (4) Stopping potential is a cutoff potential at which photocurrent becomes zero. — True. At the stopping potential the photocurrent just becomes zero.

NCERT (2026-27):
Summary – “… 4. The stopping potential (V_o) depends on (i) the frequency of incident light, and (ii) the nature of the emitter material. For a given frequency of incident light, it is independent of its intensity.”