What property distinguishes different types of electromagnetic radiation from each other?

Speed — each type travels at a different speed through space Frequency (and correspondingly wavelength) — all EM waves travel at the same speed in vacuum The type of particle they are made of Their amplitude — larger amplitude waves are lower on the spectrum

Which part of the electromagnetic spectrum has the longest wavelength?

Gamma rays Ultraviolet Infrared Radio waves

Which part of the spectrum has the highest frequency and carries the most energy per photon?

Radio waves Visible light Gamma rays Microwaves

Microwaves are used to heat food in a microwave oven. How do they heat food?

They ionise the food molecules, releasing energy as heat They cause water molecules in food to rotate rapidly, generating thermal energy through molecular friction They convert electrical energy directly into heat inside the food They reflect off metal walls and focus energy on the food

Why does ultraviolet radiation cause sunburn but visible light from the same Sun does not?

UV radiation is hotter than visible light UV photons have higher energy (higher frequency) and can break chemical bonds in DNA and skin cells; visible light photons carry too little energy to cause this damage UV light travels faster than visible light and impacts cells with more force UV radiation is absorbed by water in skin, which then gets hot and burns

Infrared radiation is associated with heat. How does this work?

Infrared is fire — all heat sources emit fire particles All objects above absolute zero emit infrared radiation proportional to their temperature; when absorbed, infrared increases the kinetic energy (temperature) of the absorbing object Infrared waves physically push molecules and force them to heat up Infrared radiation is only emitted by burning objects, not ordinary warm objects

Why are X-rays used to image broken bones but not soft tissues?

X-rays are reflected by bone but absorbed by soft tissue, creating the image X-rays are absorbed by dense materials like bone but pass through soft tissue — the difference in absorption creates contrast in the image X-rays light up bones because calcium is fluorescent under X-ray illumination Bones emit X-rays naturally, which cameras then detect

The ozone layer in the upper atmosphere absorbs most of the Sun's UV-C and UV-B radiation. Why is this important for life on Earth?

UV radiation would cool the Earth too much — the ozone layer keeps us warm UV-B and UV-C have enough energy to damage DNA — without the ozone layer, high levels of UV radiation would cause cancer and destroy many organisms The ozone layer blocks radio waves that would otherwise interfere with brain function Ozone reflects visible light back into space — without it, Earth would be too bright

Which type of electromagnetic radiation is used by your TV remote control?

Radio waves Ultraviolet X-rays Infrared

Astronomers observe the universe across the entire electromagnetic spectrum, not just in visible light. Why?

Visible light is too slow to carry information from distant galaxies Different objects and processes emit strongly at different wavelengths — radio, infrared, X-ray, and gamma observations reveal phenomena invisible to optical telescopes All EM waves carry the same information — it is purely a matter of which telescopes are cheaper Visible light is absorbed by the atmosphere before reaching telescopes