Choose the correct option for the following Assertion (A) and Reason (R).

Question

G1 Physics · Accepted Answer

For a point source, intensity varies approximately as 1 ÷ r². Therefore moving the source farther away decreases the photon arrival rate at the photocathode and hence can reduce the saturation current. However, the energy of each photon remains hν because the frequency is unchanged by the source distance. The stopping potential is determined by eV₀ = hν−φ, so it remains unchanged when only distance is changed. Thus both Assertion and Reason are true, and the Reason correctly explains the Assert…