Question

photoelectric work function of metal is 3.2ev.find the threshold wavelength

Answer 1

work function =3.2 ev = 3.2 × 1.6×10^-19

work function = hV = h c/threshold wavelength
Here c = speed of light and h =plank constant

3.2 × 1.6×10^-19 = 6.626 × 10-³⁴ ×3 ×10^8/wavelength

threshold wavelength = 6.626 × 10-³⁴ ×3 ×10^8/3.2 × 1.6×10^-19

threshold wavelength = (6.626×3/3.2×1.6) ×10^-7

threshold wavelength = 3.88 × ×10^-7 m