MHT CET202020 Oct 2020Morning ShiftPhysicsDual Nature of MatterActual
A photon of wavelength 3315 Ã… falls on a photocathode and an electron of energy 3 10⁻¹⁹ ~J is ejected. The threshold wavelength of photon is [Planck's constant (h) =6.63 10⁻³⁴ ~J - s , velocity of light .( c )=3 10⁸ ~m / s ]
Options
- A6630 Å
- B3315 Å
- C5000 Å
- D1130 Å
Correct answer
A. 6630 Å
Step-by-step solution
₀= h c -E= 6.63 10⁻³⁴ 3 10⁸ 3315 10⁻¹⁰ -3 10⁻¹⁹=(6-3) 10⁻¹⁹=3 10⁻¹⁹ ₀= hc ₀ = 6.63 10⁻³⁴ 3 10⁸ 3 10⁻¹⁹ 6630 ~Å