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JEE Mains · Physics · STD 12 - 11. Dual nature of radiation and matter
Let \(K_{1}\) and \(K_{2}\) be the maximum kinetic energies of photo-electrons emitted when two monochromatic beams of wavelength \(\lambda_{1}\) and \(\lambda_{2}\), respectively are incident on a metallic surface. If \(\lambda_{1}=3 \lambda_{2}\) then
- A \(K_{1} > \frac{K_{2}}{3}\)
- B \(K _{1} < \frac{ K _{2}}{3}\)
- C \(K_{1}=\frac{K_{2}}{3}\)
- D \(K _{2}=\frac{ K _{1}}{3}\)
Answer & Solution
Correct Answer
(B) \(K _{1} < \frac{ K _{2}}{3}\)
Step-by-step Solution
Detailed explanation
\(\frac{ hc }{\lambda_{1}}-\phi= K _{1}\) \(\frac{ hc }{\lambda_{2}}-\phi= K _{2}\) \(\lambda_{1}=3 \lambda_{2}\) \(3 K _{1}=\frac{3 hc }{\lambda_{1}}-3 \phi\) \(3 K _{1}=\frac{h c }{\lambda_{2}}-3 \phi\) \(3 K _{1}= K _{2}-2 \phi\) \(3 K _{1}< K _{2}\)…
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