Abumblebee buzzes past you at 3 m/s. the frequency of the hum made by its wings is 152 hz. assume the speed of sound to be 342 m/s. what is the observed frequency of the hum as the bumblebee approaches you?

155 hz
153 hz
150 hz
149 hz

Spend time observing or thinking about events that involve matter and energy. which events can you explain? which events can’t you explain?

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

To a of 4 x hz is 1. 0. mm nm nm