Question

Two light rays of wavelength \(\lambda\) and \(\frac{\lambda}{4}\) incident on the surface of a photo sensitive material emit electrons with max kinetic energy \(E\) and \(6E\) respectively. The work function of the material is (\(h\) = Planck’s constant, \(c\) = velocity of light in free space)

• A. \(\frac{hc}{\lambda}\)
• B. \(\frac{hc}{2\lambda}\)
• C. \(\frac{2hc}{5\lambda}\)
• D. \(\frac{3hc}{5\lambda}\)

Hint:

Always solve for the kinetic energy term first and then eliminate it to find the work function. This avoids dealing with multiple fractions for \(\phi\).

Answer 1

The Correct Option is C