Which of the following is true about radio waves? A. Radio waves can carry energy through matter but not through the vacuum of space.
B. Radio waves can carry energy through both matter and the vacuum of space
C. Radio waves can carry energy through the vacuum of space but not through matter.
D. Radio waves carry energy through neither matter nor the vacuum of space.

Ahair dryer is basically a duct in which a few layers of electric resistors are placed. a small fan pulls the air in and forces it through the resistors where it is heated. air enters a 1200 w hair dryer at 100 kpa and 22°c and leaves at 47°c. the cross-sectional area of the hair dryer at the exit is 60 cm2. neglecting the power consumed by the fan and the heat losses through the walls of the hair dryer, determine (a) the volume flow rate of air at the inlet and (b) the velocity of the air at the exit.