Can someone help me please

A150 w lamp emits light of wavelength 590 nm uniformly in all directions. what is the photon flux (photons per unit area per unit time) on a small screen at a distance 2.3 m from the lamp? assume the photons are uniformly distributed over the surface of a sphere of radius 2.3 m.

If a tank filled with water contains a block and the height of the water above point a within the block is 0.8 meter, what is the pressure at point a?

Why is the energy that results from a roller coaster's position at the top of a hill referred to as potential energy?