Threshold wavelength for a metal having work function Wo is X. What is the threshold wavelength for the metal having work function 2Wo?
Correct answer: C. λ/2
- A. 4λ
- B. 2λ
- C. λ/2
- D. λ/4
Explanation
HgWo = h c/λ (i) 2Wo= h c/λ1 (ii) Putting equation (i) equal to (ii), we get2=λ/λ1 or λ1=λ/2 1 (ii)
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Classical physics cannot explain blackbody radiation and related observations, leading to Planck’s quantum theory, in which energy is emitted or absorbed in discrete packets. Photons provide the particle model of light, with energy and momentum linked to frequency and wavelength, including the photoelectric effect and its threshold frequency.
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