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Let K 1 and K 2 be the maximum kinetic energies of photo-electrons emitted when two monochromatic beams of wavelength λ 1 and λ 2 , respectively are incident on a metallic surface. If λ 1 = 3 λ 2 then:

1. 3 K K 2 1 >
2. 3 K K 2 1 <
3. 3 K K 2 1 =
4. 3 K K 1 2 =

Correct answer: 3 K K 2 1 <

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