Edexcel iGCSE Physics -3.13 Effects and Risks of Electromagnetic Waves- Study Notes- New Syllabus

Dangers of Electromagnetic Radiation and Protective Measures

Electromagnetic (EM) waves transfer energy. If the energy absorbed by the human body is too large, it can cause damage to body tissues and cells. The severity of harm depends mainly on the frequency and energy of the radiation.

Key Idea

• Higher frequency EM waves carry more energy.
• Excessive exposure can damage cells and tissues.
• Different EM waves cause different types of harm.

Wave Relationship (Energy Context)

All electromagnetic waves obey:

\( \mathrm{c = f\lambda} \)

• Higher frequency → shorter wavelength → higher energy.
• Higher energy waves are generally more dangerous.

Detrimental Effects of Specific Electromagnetic Waves

Explanation of the Dangers

• Microwaves: Can heat internal tissues without pain being felt immediately.
• Infrared: Causes excessive heating of the skin, leading to burns.
• Ultraviolet: Damages skin cells and can cause eye damage or blindness.
• Gamma rays: Penetrate deep into the body and can alter DNA, leading to cancer.

Simple Protective Measures

• Limit exposure time.
• Increase distance from the radiation source.
• Use shielding and protective equipment.

Examples of Protection

• Microwaves: Metal shielding in microwave ovens.
• Infrared: Heat-resistant gloves and protective clothing.
• Ultraviolet: Sunscreen, sunglasses, protective clothing.
• Gamma rays: Lead shielding, restricted exposure, remote handling.

Key Idea

• Risk increases with frequency and exposure time.
• Protective measures reduce energy absorbed by the body.
• High-energy radiation requires strong shielding.

Important Points to Remember

• Not all EM waves are equally dangerous.
• Ionising radiation (UV, X-rays, gamma rays) is most harmful.
• Safety measures are essential in medical and industrial use.