Physics 9702 · AS & A Level · Characteristics of alternating currents
Characteristics of alternating currents — practice question
For long-distance communication, the reflection of radio waves by the ionosphere has largely been superseded by satellite communication.
(a)[4]
State and explain two reasons that this change has happened.
(b)[2]
The radio link between a geostationary satellite and Earth may be attenuated by as much as $190\,\text{dB}$. Suggest why, because of this attenuation, the uplink and downlink frequencies must be different.
Worked solution & mark scheme
This 6-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Any two disadvantages of ground-based communication (for example, unreliability, limited bandwidth, or coverage problems)” …