P2.4 How are electromagnetic waves used in communications? Different electromagnetic eaves have different frequencies. This affects their properties and the effect that other materials have on them. Some frequencies can be used for transmitting information:...
P2.2 Which types of electromagnetic radiation harm living tissue and why? When living cells absorb radiation, damage can occur in different ways: The heating effect can cause damage Ionising radiation, such as ultraviolet radiation, can damage cells, causing ageing of...
P2.3 What is the evidence for global warming, why might it be occurring, and how serious a threat it is? The sun emits electromagnetic radiation with a principle frequency that increases with temperature – the Earth is surrounded by an atmosphere that allows some of...