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MHT CET202519 Apr 2025Morning ShiftPhysicsDual Nature of MatterActual

Light of wavelength strikes a photoelectric surface and electrons are ejected with energy E . If E is to be increased to twice the original value, the wavelength changes to ₁

Options

  1. A₁ < / 2
  2. B₁=
  3. C₁> / 2
  4. D₁= / 2

Correct answer

C. ₁> / 2

Step-by-step solution

The kinetic energy E of ejected electrons is given by E = hf - , with frequency f = c/ , so: E = hc - When the energy doubles to 2E with wavelength ₁ : 2E = hc ₁ - Substituting hc = E + yields: hc ₁ = 2 ( hc - ) + = 2hc - Since > 0 , this implies hc ₁ 1 ₁ Taking reciprocals (and reversing the inequality since wavelengths are positive): ₁ > 2 This corresponds to option C .

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