When a surface is irradiated with light of wavelength `4950A`, a photocurrent appears which vanishes if a retarding potential greater than `0.6V` is applied across the photo tube. When a different source of light is used, it is found that the critical retarding potential is changed to `1.1V`. Find the work function of the emitting surface and the wavelength of the second source.

Explanation

To solve the problem, we will use the photoelectric equation, which relates the energy of the incident photons to the work function of the material and the kinetic energy of the emitted electrons.

### Step 1: Understand the Photoelectric Equation
The photoelectric equation is given by:
\[ E = W + KE \]
Where:
- \( E \) is the energy of the incident photons,
- \( W \) is the work function of the material,
...