Transverse Waves
Define amplitude and wavelength for a transverse wave.
Amplitude is the maximum distance that the wave moves from its rest position; wavelength is the distance between one point on a wave and the nearest point just like it. (e.g., crest to crest).
List two types of electromagnetic waves and one everyday source for each.
Radio waves — radio stations; visible light — the Sun or light bulbs.
Name one common use for infrared waves and one for ultraviolet waves.
Infrared — remote controls or thermal imaging; ultraviolet — sterilization of surfaces or lights that cause sunburn.
On a transverse wave, what point is the highest point called and what point is the lowest point called?
Highest point is a crest; lowest point is a trough.
Which has a higher frequency: visible light or radio waves? Which has a shorter wavelength?
Visible light has a higher frequency and a shorter wavelength than radio waves.
How are microwaves used in both everyday life and industry? Give one example of each.
Everyday — microwave ovens heat food; Industry — radar, satellite communication, or industrial heating processes.
Describe how energy relates to amplitude in transverse waves — if amplitude increases, what happens to the wave's energy?
Energy increases as amplitude increases (greater amplitude means the wave carries more energy).
Place the following in order from lowest frequency to highest frequency: microwave, ultraviolet, infrared.
Microwave (lowest), infrared, ultraviolet (highest).
On the electromagnetic spectrum, objects that give off higher temperatures emit shorter wavelengths of light. Which color of visible light is hotter, red or blue?
Blue light is hotter because it has a shorter wavelength and higher energy than red light.
Explain the difference between transverse and longitudinal waves using particle motion relative to wave direction.
In transverse waves particles move perpendicular to the direction of wave travel; in longitudinal waves particles move parallel to the direction of wave travel.
Explain why gamma rays are more dangerous to living tissue than visible light. Use frequency and energy in your explanation.
Gamma rays have much higher frequency and therefore higher photon energy; high-energy photons can ionize atoms and break molecular bonds, damaging cells and DNA.
On the electromagnetic spectrum, hotter objects give off more energy and shorter wavelengths. If a star is cooler, it appears red. If a star is hotter, what color does it appear?
Blue or white, because hotter stars emit shorter-wavelength, higher-energy light.
Given two transverse waves of the same wavelength but one has twice the amplitude of the other, compare their energy and describe an experiment or demonstration you could do in class to show this difference.
The wave with twice the amplitude carries more energy.
A demonstration: Stretch a rope or Slinky between two people. First, make a small wave by moving your hand a little. A small wave travels down the rope and barely moves a light object at the end. Then make a big wave by moving your hand more. A taller wave travels down the rope and moves the object much more. This shows that bigger waves carry more energy than smaller waves.