Physics Circle home Student Login

Home›Chapters›Dual Nature of Radiation and Matter PYQs›Photoelectric Effect: Einstein's Equation›Question 46

MHT CET 2025 (19 Apr, Shift 1) · Photoelectric Effect: Einstein's Equation

Photoelectric Effect: Einstein's Equation question from MHT CET 2025 (19 Apr, Shift 1)

Q46MHT CET 2025 · 19 APR · SHIFT 1Medium

Photoelectric Effect: Einstein's Equation

Light of wavelength λ\lambda strikes a photoelectric surface and electrons are ejected with energy E. If EE is to be increased to twice the original value, the wavelength changes to λ1\lambda_1

Show answer and solution

Answer: (c)

  1. E=hcλ−ϕE = \frac{hc}{\lambda} - \phi and 2E=hcλ1−ϕ2E = \frac{hc}{\lambda_1} - \phi.
  2. hcλ1=2hcλ−ϕ<2hcλ\frac{hc}{\lambda_1} = 2\frac{hc}{\lambda} - \phi < \frac{2hc}{\lambda}
  3. So λ1>λ2\lambda_1 > \frac{\lambda}{2}: the answer is (c).
Report a mistake

More questions on Photoelectric Effect: Einstein's Equation