Intensity And Photoelectric Current

NCERT establishes that for a fixed frequency above threshold, the intensity of light controls only how many photons strike the surface each second, and hence how many electrons are ejected. Since more incident photons liberate more electrons, the saturation photoelectric current grows in direct proportion to intensity. However, the maximum kinetic energy of each electron is set by $K_{max}=h\nu -\varphi$, which depends on frequency alone, so the stopping potential remains completely unchanged as intensity varies. The option claiming both quantities rise is wrong because the stopping potential is frequency-controlled and intensity-independent. The option claiming the stopping potential rises is wrong for the same reason, mistakenly linking it to brightness. The option claiming nothing changes is wrong because the current clearly scales with the number of photons and therefore with intensity. As stated in NCERT Class 12, Chapter 11, intensity governs the number of photoelectrons but not their maximum energy. The saturation current is reached when the anode collects every emitted electron, and its value therefore mirrors the emission rate set by the photon arrival rate. This clean separation, intensity governing count and frequency governing energy, is precisely the behaviour the classical wave theory could never reproduce. A consistency check confirms that increasing photon count naturally raises the current while leaving the per-electron energy, and thus the stopping potential, fixed.