explain the photovoltaic cells and photoconductive cells

Hi,

Electric Cells that use solar energy to generate electricity are called photo voltaic cells. Sunlight falling on the semiconductor material of the cell gives rise to a potential difference which is used for various purposes.

A photoconductive cell is a semiconductor device which begins to conduct when light falls on it. It is basically a two terminal device and its resistance varies linearly with the intensity of the light falling on it.