A very large metal plate carries a charge of `Q=-1C`. The work function for the metal is `phi = 3eV` The plate is illuminated by a `60` watt light source with a wavelength `lambda` of `330nm`. How long does it take to completely discharge the plate? (Assume that every efficient photon ejects electron which is instantly removed from the sheet surface. (All photons ejected from light source fall normally on the metal plate) (`h=6.6 xx 10^(-34) m^2 kg//s`)

Options

A. 0.005 s
B. 0.025 s
C. 0.0625 s
D. 0.01

Explanation

To solve the problem of how long it takes to completely discharge a metal plate carrying a charge of \( Q = -1C \) when illuminated with a light source, we can follow these steps:

### Step 1: Calculate the Energy per Photon
The energy of a photon can be calculated using the formula:
\[ E = \frac{hc}{\lambda} \]
Where:
...