Question

A transmitter of power P sits atop a radio tower broadcasting in all directions. A man standing on the ground a radial distance r away from the transmitter measures the intensity of the radio waves to be
A) P/(4πr2)
B) P/(πr2)

C) P/(2πr)

D) P/(r2)

What happens when you put a small ice cube in a thermally isolated container (like a Thermos) containing considerably greater volume of hot coffee?
A) Heat flows from the ice into the hot coffee. Both ice and coffee evaporate into a warm, brown fog at an equilibrium temperature that is the average of the original ice and coffee temperatures.
B) Heat flows from the hot coffee into the ice. The equilibrium temperature drops to 0 ̊C and you end up with iced coffee.
C) Heat flows from the ice into the hot coffee. The ice gets colder and the coffee begins to boil.
D) Heat flows from the hot coffee into the ice, melting the ice and warming the resulting water up to the equilibrium temperature, which is close to the hot coffee’s original temperature.

An isolated sample of an ideal gas has an initial volume V0. Its container slowly changes shape until only half the volume V0/2 remains with no change in temperature. What happens to pressure of the gas in the sample?
A) It becomes only half as great.

B) It does not change.
C) It becomes 2 times as great.

D) It becomes 4 as great.

Answer 1