Question

This question has several parts that must be comple ted sequentially. If you skip a part of the question, you will not receive any points for the skipped part, and you will not be able to come back to the skipped part. Tutorial Exercise A dish antenna with a diameter of 12.1 m receives (at normal incidence) a radio signal from a distant source, as shown in the figure below. The radio signal is a continuous sinusoidal wave with amplitude Emax = 0.35 pV/m. Assume the antenna absorbs all the radiation that falls on the dish (a) What is the amplitude of the magnetic field in this wave? |(b) What is the intensity of the radiation received by the antenna? (c) What is the power received by the antenna? Step 1 (a) The amplitude of the magnetic field is E. max Bmax V/m 3.5 x10 1.17X x 108 m/s 3 Your response is off by a multiple of ten. x 1016 T

Answer 1

Amplitude of magnetic field, B = E/C = 0.35 times 10^-6/3 times 10^8 T = 1.16 times 10^-15 T Intensity, I = CE_0 E^2/2 = 3 times 10^8 times 8.85 times 10^-12 times (0.35 times 10^-6)62/2 tildeequal 1.626 times 10^-16 v/m power, p = Intensity times Area Here, area, A = pi r^2 Considering the area to be circular. It may change according to the shape. therefore area, A = pi times (12.1/2)^2 tildeequal 115 m^2 therefore power, p = 1.626 times 10^-16 times 115 w tildeequal 1.87 times 10^-14 w.