When ultraviolet light is incident o its stopping potential is V0 and the maximum kinetic energy of the photoelectrons i the ultraviolet light is replaced by X- rays, both Vo and Kmax increase. ?

Since the frequency of ultraviolet light is less than the frequency of X-rays, the
energy of each incident photon will be more for X-rays
KEphotoelectron=hv–ϕ
Stopping potential is to stop the fastest photoelectron
V∘= hv/e ​– ϕ/e​
and V∘ both increases. So, KEmax
But KE ranges from zero to KEmax because of loss of energy
due to subsequent collisions before getting ejected and not due to
range of frequencies in the incident light.