Light and the EM spectrum (Extended response)

Question 1

Exposure to certain types of electromagnetic radiation can have harmful effects on the human body

Describe how exposure to EM radiation can be harmful

Your answer should refer to the types of EM radiation and the damage that they may cause

Answer 1

• radio waves and visible light don’t cause damage to humans
• the other five members do
• microwaves are absorbed by water molecules so can lead to internal heating of body cells
• infared radiation can cause burns to skin
• UV radiation can damage the eyes leading to conditions
• it can also cause sunburn leading to skin cancer
• x-rays and gamma rays can both lead to cellular damage and mutations, which can cause cancer
• this is because they are ionising radiation

Question 2

Describe how the EM spectrum is useful to humans. Refer to specific members of the EM spectrum in your answer

Answer 2

• radio waves: broadcasting, communications, satellite transmissions
• microwaves: cooking, communication, satellite
• infared: cooking, thermal imaging, short-range communications, optical fibres, tv remotes, security systems
• visible light: vision, photography, illumination
• ultraviolet: security marking, fluorescent lamps, detecting forged bank notes, disinfecting wat-er
• x-rays:observing internal structures, airport scanners, medical
• gamma rays: sterilising food and medical equipment, detection of cancer and its treatment