The photometer is a device that converts light to voltage which is read out by the digital multimeter (DMM). This is due to the photoelectric effect. (Einstein won his Nobel Prize for his explanation of the photoelectric effect.) In the photoelectric effect, light hits a piece of metal. Quantum mechanics tells us that light can be thought of as tiny packets of energy called photons. The photons are absorbed by electrons and increase the energy of the electrons. Some of the electrons become so energetic that they escape from the metal. In other words electrons are emitted from the metal, producing a current that is amplified by the photometer. The current goes through a resistor in the photometer. Ohm's law (V=IR) tells us that current I going through a resistor R is associated with a voltage drop V. The DMM measures the voltage drop across the resistor. Saturation occurs when the metal emits the maximum flux of electrons that it can produce. (Or it may be the maximum amplification of the photometer.)
What does a photometer do?
B. It converts light into electric current.

A. It emits light.
B. It converts light into electric current.
C. It measures the frequency of light.
D. It emits sound.

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

Examine the equation. 23490th→23088ra+42he what kind of barrier would you need to block the radioactive particles from this reaction? a.a piece of paper b.a sheet of aluminum foil c. a two-inch block of lead d. a solid concrete block

The unit of resistivity is the: ohm ohm-cm volt coulomb