How many free electrons are there in 2.55 cm^ ^ 3 of pure Silicon Note N = Vp and rho = 1.54 free electrons / cm ^3 A: 3.93 x 10^20 free electrons
B: 6.32 x 10^20 free electrons
C: 3.93 x 10^22 free electrons
D: 6.32 x 10^2× free electrons

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Ammonia enters the expansion valve of a refrigeration system at a pressure of 10 bar and a temperature of 18oc and exits at 6.0 bar. the refrigerant undergoes a throttling process. determine the temperature, in oc, and the quality of the refrigerant at the exit of the expansion valve.

What is the energy of a photon of ultraviolet radiation with a frequency of 4.4 × 1015 hz? planck’s constant is 6.63 × 10–34

Lightning is an example of what phenomenon? a release of a large amount of energyan absorption of a large amount of energya natural electric circuita natural electric current