Intensity and frequency of incident light both are doubled.
Then, what is the effect on stopping potential and saturation current.

Explanation

By increasing the frequency of incident light energy of incident light will increase.
So, maximum kinetic energy of photoelectrons will also increase. Hence, stopping potential will
increase.
Further, by doubling the frequency of incident light energy of each photon will be doubled. So,
intensity itself becomes two times without increasing number of photons incident per unit are
per unit time. Therefore, saturation current will remain unchanged.