Threshold wavelength of silver is 3250 Å. Velocity of an electron ejected by light of wavelength 2536 Å is closest to (h = 4.14 × 10⁻¹⁵ eV·s):
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Threshold wavelength of silver is 3250 Å. Velocity of an electron ejected by light of wavelength 2536 Å is closest to (h = 4.14 × 10⁻¹⁵ eV·s):

G1 Physics · Accepted Answer

K = hc(1/λ − 1/λ₀) ≈ 1240(1/253.6 − 1/325) eV ≈ 1.07 eV. Hence v = √(2Ke/mₑ) ≈ √(2 × 1.07 × 1.602 × 10⁻¹⁹ / 9.11 × 10⁻³¹) ≈ 6.1 × 10⁵ m/s. Source answer A.