water flows over niagara falls at the average rate of 2,400,000 kg/s and the average height of the water falls is about 50m. knowing that the gravitational potential energy of falling water per seccond = mass (kg) x height (m) x gravity (9.8m/s) what is the power of niagara falls how many 15 led lights bulbs could it power ?

If you chip a tooth, most likely you will go to the dentist to have the missing material filled in. currently the material used to fill in teeth is a polymer that is flexible when put in, yet is hardened to the strength of a tooth after irradiation with blue light at a wavelength of 461 nm. what is the energy in joules for a photon of light at this wavelength?