Choose the answer that explains the photoelectric effect.

metallic plates emit protons only when light of a certain minimum frequency shines on them.
metallic plates emit electrons when the cumulative effect of light causes electron movement.
metallic plates emit electrons only when light of a certain maximum frequency accumulates energy.
metallic plates emit electrons only when light of a certain minimum frequency shines on them.

taylor's experiment:

accurately measured the speed of light
locked together the phases of two light sources so that the interference pattern would not shift
showed that man's reaction time was much slower than the speed of light
showed that individual photons have wave characteristics

An internally reversible refrigerator has a modified coefficient of performance accounting for realistic heat transfer processes of where qin is the refrigerator cooling rate, qout is the heat rejection rate, and is the power input. show that copm can be expressed in terms of the reservoir temperatures tc and th, the cold and hot thermal resistances rt, c and rt, h, and qin, as where rtot rt, c rt, h. also, show that the power input may be expressed as 1.39 a household refrigerator operates with cold- and hot-temperature reservoirs of tc 5 c and th 25 c, respectively. when new, the cold and hot side resistances are rc, n 0.05 k/w and rh, n 0.04 k/w, respectively. over time, dust accumulates on the refrigerator’s condenser coil, which is located behind the refrigerator, increasing the hot side resistance to rh, d 0.1 k/w. it is desired to have a refrigerator cooling rate of qin 750 w. using the results of problem 1.38, determine the modified coefficient of performance and the required power input w under (a) clean and (b) dusty coil conditions. internally reversible refrigerator qout qin w high-temperature reservoir low-temperature reservoir th th, i tc, i tc high-temperature side resistance low-temperature side resistance w qin th tc qinrtot tc qinrtot copm tc qinrtot th tc

How many atoms of nitrogen are in the chemical formula ni(w on

What happens when you slowly pulled the carboard?