Physics Circle home Student Login

Home›Chapters›Dual Nature of Radiation and Matter PYQs›Photoelectric Effect: Einstein's Equation›Question 129

JEE Main 2019 (10 Apr, Shift 1) · Photoelectric Effect: Einstein's Equation

Photoelectric Effect: Einstein's Equation question from JEE Main 2019 (10 Apr, Shift 1)

Q129JEE Main 2019 · 10 APR · SHIFT 1Easy

Photoelectric Effect: Einstein's Equation

In a photoelectric effect experiment the threshold wavelength of the light is 380 nm. If the wavelentgh of incident light is 260 nm, the maximum kinetic energy of emitted electrons will be: Given E (in eV) = 1237/λ\lambda (in nm)

Show answer and solution

Answer: (d)

  1. Kmax=1237λ−1237λ0K_{max} = \frac{1237}{\lambda} - \frac{1237}{\lambda_0} (in eV, λ\lambda in nm)
  2. Kmax=1237(1260−1380)=1237×12098800K_{max} = 1237\left(\frac{1}{260} - \frac{1}{380}\right) = 1237 \times \frac{120}{98800}
  3. Kmax≈1.5 eVK_{max} \approx 1.5\text{ eV}, so the answer is (d) 1.5 eV.
Report a mistake

More questions on Photoelectric Effect: Einstein's Equation