Minimum photocurrent which must be passed through the circuit is — Atomic Structure Chemistry Question

💡 Solution & Explanation

To minimize the photocurrent, we need to find the configuration that minimizes the number of photoelectrons emitted per second. Photoelectric emission occurs only if the photon energy E_p = Power / n_photons is greater than the work function (4.5 × 10^-19 J). Pairing P = 2 W with n = 5 × 10^18 s^-1 gives E_p = 4.0 × 10^-19 J < work function (no emission); pairing P = 3 W with n = 9 × 10^18 s^-1 gives E_p = 3.33 × 10^-19 J < work function (no emission). The remaining gun P = 5 W with n = 4 × 10^18 s^-1 gives E_p = 1.25 × 10^-18 J > work function. Minimum photocurrent I_min = 4 × 10^18 × 1.6 × 10^-19 = 0.64 A.