What is the effect in output for changing input frequency in halfwave rectifier?

if filtered and loaded the average DC voltage will increase and the ripple AC voltage will decrease, but the peak voltage is unchanged. this is because the filter capacitor has less time to discharge into the load.

if unfiltered or unloaded the voltage cannot change. unfiltered the waveform just follows the half cycle of the input. if filtered but unloaded the output is DC at the peak voltage of the input AC.