Beyond the Rainbow

Why it matters

Your eye reads one octave of an eleven-octave keyboard. Radio, microwave, infrared, ultraviolet, X, gamma — the universe broadcasts on all of them, and your TV remote is already fluent in one.

The idea in plain words

One family, common rules. Tap the terms.

all EM waves: transverse, speed c in vacuum, need no medium

Why does the TV remote need line-of-sight but the radio doesn't?

Longer wavelengths bend around things; short ones travel like light beams

• the family speed: c — 3 × 10⁸ m/s in vacuum — radio and gamma arrive together from a star
• below red: IR — infrared: felt as heat; remotes, thermal cameras; detected by thermometer/thermopile
• beyond violet: UV — ultraviolet: ionising in excess; vitamin D, sterilising, fluorescence; detected by photographic film
• the sharp end: X & γ — penetrating and dangerous: bone imaging, cancer therapy — and shielding rules
• Remote: IR — short λ, easily blocked, absorbed by walls
• Radio: λ of metres — diffracts around obstacles

Predict first

Which has the HIGHEST frequency (and energy)?

Energy rises with frequency: radio is the gentle end, gamma the fierce one. Transmitter POWER and per-wave ENERGY are different things.

• Gamma rays — correct
• Radio waves
• Visible light — we can see it

What you do

Match each band to its day job. The ruler at the top runs long-λ (radio) to short-λ (gamma).

Check yourself

Infrared radiation is detected by…

IR sits below the eye's range; its signature is heating, so heat detectors find it.

Which is a proper use of ultraviolet?

UV kills microbes and makes security inks fluoresce. FM is radio; warming is IR/microwave.

From a supernova, radio waves and gamma rays reach Earth…

Energy changes what the wave DOES, not how fast it travels in vacuum.

• a blackened-bulb thermometer / thermopile — it heats things — correct
• the naked eye
• a magnet
• Sterilising surgical instruments and checking fake notes — correct
• Broadcasting FM
• Warming food
• at the same time — same c in vacuum — correct
• gamma first — higher energy is faster
• radio first — long waves glide