Copy each passage into your book and fill in the numbered gaps using the word bank. Then check your answers. ← All topics
1. Transverse and longitudinal waves (C+S)
Waves transfer (1)______ from one place to another without transferring matter. In a (2)______ wave, the oscillations are perpendicular to the direction of energy transfer – for example, ripples on water and all electromagnetic waves. In a (3)______ wave, the oscillations are parallel to the direction of energy transfer; these waves have (4)______ and rarefactions. (5)______ waves in air are longitudinal.
Word bank: compressions · energy · longitudinal · sound · transverse
Check your answers
1 energy · 2 transverse · 3 longitudinal · 4 compressions · 5 Sound
2. Properties of waves (C+S)
The (1)______ of a wave is the maximum displacement of a point from its rest position. The (2)______ is the distance from one point on a wave to the same point on the next wave. The (3)______ is the number of waves passing a point each second, measured in hertz. The period is the time for one wave: T = 1 ÷ f. Wave speed = frequency × (4)______ (v = fλ). The speed of sound in air can be measured using two people, a loud sound and a (5)______ over a measured distance.
Word bank: amplitude · frequency · stopwatch · wavelength · wavelength
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1 amplitude · 2 wavelength · 3 frequency · 4 wavelength · 5 stopwatch
3. Reflection and refraction (C+S)
Waves can be reflected, absorbed or (1)______ at the boundary between two materials. For reflection, the angle of incidence equals the angle of reflection, both measured from the (2)______. Reflection from a smooth surface in one direction is (3)______ reflection; from a rough surface it is diffuse. Refraction is a change in direction because the wave changes (4)______ as it crosses a boundary at an angle. When light enters glass, it slows down and bends (5)______ the normal.
Word bank: normal · specular · speed · towards · transmitted
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1 transmitted · 2 normal · 3 specular · 4 speed · 5 towards
4. The electromagnetic spectrum (C+S)
Electromagnetic waves are (1)______ waves that all travel at the same speed through a (2)______. In order of increasing frequency, they are: radio waves, microwaves, (3)______, visible light, ultraviolet, X-rays and gamma rays. Our eyes can only detect (4)______ light. Radio waves can be produced by (5)______ in electrical circuits, and when they are absorbed they can create an alternating current.
Word bank: infrared · oscillations · transverse · vacuum · visible
Check your answers
1 transverse · 2 vacuum · 3 infrared · 4 visible · 5 oscillations
5. Uses and dangers of EM waves (C+S)
Radio waves are used for television and radio; (1)______ for satellite communications and cooking; infrared for heaters and cameras; visible light for (2)______ optic communications; ultraviolet for energy-efficient lamps and sun tanning; X-rays and gamma rays for medical imaging and treatments. Ultraviolet makes skin age early and increases the risk of skin (3)______. X-rays and gamma rays are (4)______ radiation that can cause mutation of (5)______ and cancer.
Word bank: cancer · fibre · genes · ionising · microwaves
Check your answers
1 microwaves · 2 fibre · 3 cancer · 4 ionising · 5 genes
6. Sound, ultrasound and seismic waves (S only)
Humans can hear sounds from about 20 Hz to (1)______ Hz. Ultrasound has a higher frequency and is partly (2)______ at the boundary between two materials; timing the echoes is used for medical scans and for echo sounding to find the depth of water. Earthquakes produce P-waves, which are (3)______ and travel through solids and liquids, and S-waves, which are transverse and can only travel through (4)______. The S-wave shadow zone shows that the Earth’s outer core is (5)______.
Word bank: 20 000 · liquid · longitudinal · reflected · solids
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1 20 000 · 2 reflected · 3 longitudinal · 4 solids · 5 liquid
7. Lenses and visible light (S only)
A (1)______ lens brings parallel rays of light together at the principal focus; a (2)______ lens spreads them out. The distance from the lens to the principal focus is the (3)______ length. A real image can be projected onto a screen; a (4)______ image cannot. Magnification = image height ÷ object height. A coloured object looks that colour because it (5)______ that colour of light and absorbs the others.
Word bank: concave · convex · focal · reflects · virtual
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1 convex · 2 concave · 3 focal · 4 virtual · 5 reflects
8. Black body radiation (S only)
All bodies emit and absorb (1)______ radiation. The hotter the body, the more infrared radiation it emits in a given (2)______. A perfect black body absorbs all the radiation that hits it; it is also the best possible (3)______. A body at constant temperature absorbs radiation at the (4)______ rate as it emits it. The temperature of the Earth depends on the balance between the radiation it absorbs and the radiation it (5)______ into space.
Word bank: emits · emitter · infrared · same · time
Check your answers
1 infrared · 2 time · 3 emitter · 4 same · 5 emits
