Aspiral spring of a spring balance is 25.0cm long when 5n hangs on it and 30.0cm long when the weight is 10n. what is the length of the spring if the weight is 3n, assuming hooked law is charged

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

This is for my 8th grade science class, i really don’t understand. can someone me? , lol.

What are the dimensions of the cross section that passes through the points a, f, g, and d?