A long beach afternoon leaves Viggo sunburned. The radio waves that crossed his skin all afternoon did nothing at all.
Both bands reached him. Why does one damage skin while the other passes straight through? The energy rule decides it.
An electromagnetic wave with a greater frequency carries more energy.
When matter absorbs a wave, the wave's energy lands in that matter.
Ultraviolet light carries enough energy to damage skin cells.
Radio waves carry far less energy, and a body barely absorbs them: they pass through harmlessly.
Both conditions matter: the wave must be absorbed, and the absorbed energy must be large enough to harm.
A wave that is not absorbed delivers no energy to the body, whatever its frequency.
Absorbed X-rays can harm living tissue; absorbed visible light from a lamp does not. Why?
X-rays have a far greater frequency than visible light.
A greater frequency means more energy, delivered wherever the wave is absorbed.
The absorbed X-rays deliver far more energy to the tissue, enough to damage cells.
Gamma rays and infrared both strike a material that absorbs them. Which could do more damage?
Energy follows frequency.
Gamma rays carry far more energy than infrared.
The gamma rays: absorbed, they deliver far more energy.
Which causes more damage to skin that absorbs it: ultraviolet light or infrared?
Why does electromagnetic radiation with a greater frequency cause more damage when it is absorbed?
Wanda says: 'Ultraviolet light can damage skin cells that absorb it, while radio waves pass through the body almost without being absorbed.' Is Wanda correct?
Sunscreen is designed to stop ultraviolet rather than visible light. Which statement explains the choice?
Of these bands, which causes the most damage to a material that absorbs it: microwaves, infrared, visible light, or X-rays?
A technician stands behind a barrier during a patient's X-ray but stands in plain view of the clinic's ordinary lamps. Which statement explains the barrier?