What is the intensity of an electromagnetic wave with a peak electric field strength of 125 V/m?
An outdoor WiFi unit for a picnic area has a 100-mW output and a range of about 30 m. What output power would reduce its range to 12 m for use with the same devices as before? Assume there are no obstacles in the way and that microwaves into the ground are simply absorbed.
A photovoltaic array of solar cells is efficient in gathering solar energy and converting it to electricity. Assume a value of 75.0 W/m2 for the average intensity of sunlight.
What area should the array have to gather energy at the rate of 250 W?
What is the maximum cost of the array if it must pay for itself in two years of operation, averaging 12.00 hours of use per day? Assume that the array earns money at the rate of 10 cents per kilowatt-hour.