You hear the engine roaring on a race car at the starting line. predict the changes in sound as the race starts and approaches the camera a. the sound of the engine will get louder and pitch lower b. the sound of the engine will get louder and pitch higher c. the sound is determined by the car and it will not change in anyway d. the sound of an engine will get louder but the pitch will not change

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