Radiations of frequencies `v_2 and v_2` are made to fall in turn, on a photosenstive surface. The stopping potential required for stopping the most energetic photoelectrons in the two cases are `V_1 and V_2` respectively. Obtain a formula for determining the threshold freqeuncy in terms of these parameters.

Explanation

To derive the formula for determining the threshold frequency (\( \nu_0 \)) in terms of the frequencies (\( \nu_1 \), \( \nu_2 \)) and the stopping potentials (\( V_1 \), \( V_2 \)), we will use the photoelectric effect equation. Here’s the step-by-step solution:

### Step 1: Write the Photoelectric Equation
The general photoelectric equation is given by:
\[ E \cdot V_0 = h \nu - \phi_0 \]
where:
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