The threshold frequency of a metal is `f_0`. When the light of frequency `2f_0` is incident on the metal plate, the maximum velocity of electrons emitted is `v_1`. When the frequency of the incident radiation is increased to `5f_0`, the maximum velocity of electrons emitted is `v_2`. Find the ratio of `v_1 andv_2`.

Explanation

To solve the problem, we will use Einstein's photoelectric equation, which relates the kinetic energy of emitted electrons to the frequency of the incident light and the work function of the metal.

### Step-by-Step Solution:

1. **Understand the Problem**:
We have a metal with a threshold frequency \( f_0 \). When light of frequency \( 2f_0 \) is incident on the metal, the maximum velocity of emitted electrons is \( v_1 \). When the frequency is increased to \( 5f_0 \), the maximum velocity becomes \( v_2 \). We need to find the ratio \( \frac{v_1}{v_2} \).

2. **Write Einstein's Photoelectric Equation**:
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