What is the different between solar cell & photo cell ( photo electric effect exp... ) ?

I know this is a homework question, so I'll ask you two questions:

What is the input to and what is the output from each device?

Input :- electro magnetic wave (light)
Output :- Volage(emf) or current

You have the output wrong and you didn't specify which device has what output(s).

Is Photo cell's out put is Current

Nope.

A photocell acts as a resistor.its resistance decreases in the day and increases at night. A photo cell is made by doping a group 14 element with group 15 for a n-type and group 13 for a p-type. The solar cell works on sun's radiation just as the photo cell but is not a resistor.