CIE AS & A Level Physics : 25.3 Hubble’s law and the Big Bang theory – Exam style question – Paper 4


(a)      State three features of the orbit of a geostationary satellite.

(b)     A signal is transmitted from Earth to a geostationary satellite. Initially, the signal has power \(3.2\) kW. The signal is attenuated by \(194\) dB.

Calculate the signal power received by the satellite.

(c)      Suggest one advantage and one disadvantage of the use of geostationary satellites compared with polar-orbiting satellites for communication between points on the Earth’s surface.



(a)     Any three from:

above the Equator

period \(24\) hours

orbits west to east

one particular orbital radius

(b)     attenuation = \(10 lg( P_{1} / P_{2})\)

194 = \(10 lg (3.2 \times 10^{3} / P_{2})\)

\(P_{2}\) = \(1.3 \times 10^{–16}\) W

(c)      advantage: e.g. no tracking required

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