Question 1a
Waves can be described as either transverse or longitudinal.
(a)
Illustrate and explain the terms transverse and longitudinal, giving examples of each.
[6]
Question 1b
A satellite passing Neptune communicates with Earth using a microwave transmitter with an output power of 24.0 W and wavelength 78 900 µm.
The satellite's controller is located on Earth, at a distance of 4.40 × 1012 m when the signal is transmitted.
(b)
For this communication
(i)
Calculate the time taken for the signal to be detected by the controller.
[1]
(ii)
Calculate the energy of a microwave photon.
[2]
Question 1c
The controller dish aerial has an effective area of 258 m2.
(c)
For the communication from part (b)
(i)
Determine the power received by the controller dish aerial. You may assume that the power transmitted by the satellite radiates uniformly in all directions.
[2]
(ii)
The actual power received by the controller dish aerial is 1.4 × 10−15 W. Suggest why this is different to the calculated power received.
[2]
(iii)
Calculate the rate at which microwave photons arrive at the controller dish aerial.
[2]
