alleryMaximum velocity of photoelectrons from a metal of work function 2 eV, illuminated by 200 nm light:
A≈ 1.42 × 10⁶ m/s
B3 × 10⁸ m/s
C10³ m/s
DCannot determine
Answer & Solution
Correct answer: A. ≈ 1.42 × 10⁶ m/s
E_photon = 1240/200 = 6.2 eV.
KE_max = 6.2 - 2 = 4.2 eV = 6.72 × 10⁻¹⁹ J. v_max = sqrt(2 KE/m) = sqrt(2 × 6.72e-19 / 9.11e-31) ≈ 1.21 × 10⁶ m/s. (Close to 10⁶ m/s.)
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