Electromagnetic radiation with a wavelength of 640 nm appears as orange light to the human eye. The frequency of this light is Hz

An input force of 7 n is applied to a machine with a mechanical advantage of 1.75. what is the maximum the machine could lift? 12.25 n7n7.25 n26.2 n

Glass is transparent to visibile light under normal conditions; however, at extremely high intensities, glass will absorb most of the light incident upon it. this works through a process known as multiphoton absorption. in this process, several photons are absorbed at the same time. if very intense light whose photons carry 2ev of energy is shined onto a material with a band gap of 4ev, that light can be absorbed through two-photon absorption, because two photons have the right amount of energy to bridge the band gap. what is the minimum number of photons of 800-nm light that are needed to equal or exceed the band gap of fused silica glass

Could someone . i have tried to solve myself but my calculation is off