a. Suppose that a point source is radiating light waves at a rate of 10 W. Calculate the intensity in mW/m² or 10^-3 W/m² at a distance of 20 m from the source.

Enter a number with 1 digit behind the decimal point.

b. A plane electromagnetic wave of intensity 8.3 W/m² strikes a dark surface of area 67 cm² perpendicular to the approaching wave and is completely absorbed.

Find the force that the wave exerts on the mirror in picoNewton.

Enter an integer.