Q1. Microwave signals are beamed between two mountaintops 51 apart. How long does it take a signal to travel from one mountaintop to other?

Q2. Solar cells convert the energy of incoming light to electric energy; a good quality cell operates at an efficiency of 15 percent. Each person in the United States uses energy (for lighting, heating, transportation, etc.) at an average rate of 11. Though sunlight varies with season and time of day, solar energy falls on United States at an average intensity of 200. Assuming you live in an average location, what total solar-cell area would you need to provide all of your energy needs with energy from the sun?