1. **Sail. Spacecraft could use a light \"sail\" that absorbs electromagnetic radiation for steering. Former UCI Physics Professor Greg Benford and his identical twin brother James irradiated thin sheets of carbon with microwaves to test this idea. They shot a 10 kW, 7 GHz microwave beam at a carbon-carbon material with mass density of 5 g/m?; at the \"sail,\" the area of the beam was 7 cm?. (a) What was the magnitude of the electric field in the vacuum in front of the sail? (b) What was the magnitude of the magnetic field in the vacuum in front of the sail? (c) What was the momentum density in the vacuum in front of the sail? (d) If these microwaves are absorbed by the sail without reflection, what accelera- tion of the sail is expected?' Compare to the acceleration due to gravity. (e) Make an order of magnitude estimate of the number of photons in one period of the microwave beam. Is the classical approximation that ignores the discrete, quantized nature of light a good one