Practice question

Given: What is the work function of a metal if radiation of wavelength 242 nm just ionizes it? ( h = 6.626 × 10⁻³⁴ J s, c = 3.0 × __10POW₈__m s^{-1, N_A = 6.022 × __10POW₂₃__mol^{-1 ) These values define the system as per NCERT data. Formula: Energy per photon = hc/lambda = frac6.626 × 10⁻³⁴ × 3.0 × __10POW₈₂₄₂__ × 10⁻⁹= 8.22 × 10⁻¹⁹ J. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Per mole = 8.22 × 10⁻¹⁹ × 6.022 × __10POW₂₃__= 494 kJ mol^{-1 . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.