1. The peak power of a 6ft. diameter antenna is 10 watts and its duty cycle is 0.250. The wave length is 0.03m/cycle. Find the power density in mw/cm2 at 50 meters from the antenna.
2-The activity of an isotope was determined to be 4000mci on Monday at 10.00 am on Tuesday at the same time its activity was found to be 3200mci. Find this isotope's half-life.