15. A photon of energy 3 keV collides elastically with an electron initially at rest. If the photon emerges at an angle of 60°, calculate
(a) the kinetic energy of the recoiling electron and
(4mks)
(b) the angle at which the electron recoils.
(4mks)
I​

Acoal-fired plant generates 600 mw of electric power. the plant uses 4.8 x 10^6 kg of coal each day, and the heat of combustion of coal is 3.3x 10^7 j/kg. the steam that drives the turbines is at a temperature of 300° c, and the exhaust water is at 37° c. (a) what is the overall efficiency of the plant for generating electric power? (b) how much thermal energy is exhausted each day? (c) what is the change in entropy of the universe for this heat engine? (d) using the same heat reservoirs, what is the maximum possible (carnot) efficiency for a heat engine?

What do the atoms of elements in the same group have in common? a. they have the same atomic numbers. b. they have the same average atomic masses. c. they have the same number of electron shells. d. they have the same number of electrons in their outermost shells.

Atoaster oven has a resistive heating element. the average rate at which it dissipates energy as thermal energy is 1.00 \(\rm kw\). in the united states, emf amplitude in household circuits is \(\mathcal e_{\max}\) = 170 \({\rm \; v}\) and the \(\rm ac\) oscillation rate is 60 \(\rm hz\). part a what is the root-mean-square current through the heating element?