IGCSE 0625 / Section 3.3 / Core

When energy does harm.

The same spectrum that warms your skin and shows you the world can also burn, blind, and trigger cancer. The higher the frequency, the more energy each wave carries, and the more harm it can do.

The key idea

The danger of an electromagnetic wave rises with its frequency, because higher frequency waves carry more energy. Microwaves heat the water in cells, infrared burns skin, and ultraviolet, X-rays and gamma rays are energetic enough to damage or mutate living cells.

Definition · learn the exact words

The energy carried by an electromagnetic wave increases with its frequency, so the high frequency waves (ultraviolet, X-rays and gamma rays) carry enough energy to damage or mutate living cells.

higher frequency → more energy → more harm

Microwaves cause internal heating of cells, infrared causes skin burns, ultraviolet causes skin cancer and eye damage, X-rays and gamma rays cause cell mutation and cancer.

Section 01

Send radiation at living tissue.

Choose a band and watch how it interacts with cells, gently for low frequencies and damagingly for the high frequency end.

Stage 1 · Learn

Check harmful effects

Four quick checks. Each correct answer earns XP and lights this skill on your star map.

Quick check+10 XP

Excess exposure to which radiation can cause skin cancer and eye damage?

Quick check+10 XP

Microwaves are harmful to the body mainly because they cause...

Quick check+10 XP

Which carries the most energy per wave?

Quick check+10 XP

A hazard of too much infrared radiation is...

Section 02

Higher frequency, greater danger.

Each region affects the body differently, and the harm grows toward the high frequency end of the spectrum.

RadiationHarmful effect
MicrowavesInternal heating of body cells
InfraredSkin burns from excess heating
UltravioletDamage to surface cells and eyes, skin cancer
X-rays and gamma raysMutation of cells, cancer
Examiner trap

It is the high frequency end of the spectrum, ultraviolet, X-rays and gamma rays, that is the most dangerous, because the energy carried rises with frequency. Microwaves do not scorch like a flame; they heat the water inside cells from within.

Stage 2 · Exam

Exam-style questions

Unlocks once the four checks above are done. Worth more XP, written in the style of Paper 2.

Finish the four checks above to unlock the exam questions
Exam style+20 XP

Ultraviolet radiation is more dangerous to the skin than visible light because it...

Exam style+20 XP

Which list places the radiations in order of increasing harm to living cells?

Exam style+20 XP

Repeated exposure to X-rays and gamma rays is dangerous chiefly because they can...

Skill unlocked

Harmful effects, mastered.

The hazards of the spectrum are mapped. Keep the chain going.

-Rank -Level -Score -Topics
Go deeper · practice
Six original Cambridge-style questions
How harm rises with frequency, microwave heating, infrared burns, and the damage from ultraviolet, X-rays and gamma rays. Attempt each, then reveal the worked solution.
Stage 3 · master the unit
Waves challenge
Mixed questions across the whole unit, each one worth XP. Start this only when you feel confident across every topic in the unit, not just harmful effects.
Start the unit challenge →