Large radio telescopes, like the one in Arecibo, Puerto Rico, can detect extremely weak signals. Suppose one radio telescope is sensitive en

Large radio telescopes, like the one in Arecibo, Puerto Rico, can detect extremely weak signals. Suppose one radio telescope is sensitive enough to detect a signal which lays down only 0.95 pW of power on an area of 6.1 × 1017 m2. (a) What would be the total power that would be received by the antenna, assuming that its diameter is 380 m? (b) What would be the power of a source at 17000 ly distance from Earth that could provide such a signal? A light-year is the distance light travels in one year.