Question

What happens to kinetic energy when threshold frequency is increased ?

Answer 1

Let's say you can increase the threshold frequency `nu_0`.

Then, from Einstein's photoelectric equation,

`K_(max) = hnu - phi_0`
`implies K_(max) = hnu - hnu_0`

Thus, if you keep `nu`, i.e. the frequency of incident radiation constant, then increase of `nu_0` proportionately decreases `K_(max)`.