# When light falls on metal

**Classical Mechanics**Level 3

Light of frequencies \(\SI{5}{\hertz} \) and \(\SI{12}{\hertz} \) fall on two pure sheets of the same metal of same thickness, thus releasing electrons from the sheets. If it is known that the ratio of the maximum kinetic energies of the electrons emitted from the first sheet to the second sheet is \(1:3\), find the threshold frequency of the given metal.

**Details and assumptions**:

- Threshold frequency is the minimum frequency which is required to perform photoelectric effect.
- The sheets of metals are equal in size and shape.
- Give your answer(in Hz) to two decimal places.