Waves & The Electromagnetic SpectrumEdexcel IGCSE Physics: Flashcards
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What do waves transfer, and what don't they transfer?
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- What do waves transfer, and what don't they transfer?
- Waves transfer energy and information; they do not transfer matter.
- Define amplitude.
- The maximum displacement of a point on a wave from its undisturbed (rest) position.
- Define wavelength.
- The distance from one point on a wave to the identical point on the next wave (e.g. crest to crest).
- Define frequency.
- The number of complete waves passing a fixed point per second, measured in hertz (Hz).
- How are frequency and time period related?
- f = 1/T, where T is the time period.
- State the wave equation.
- v = f × λ (speed = frequency × wavelength).
- What is the difference between transverse and longitudinal waves?
- Transverse: vibrations are perpendicular to the direction of energy transfer. Longitudinal: vibrations are parallel to the direction of energy transfer.
- What is the Doppler effect?
- The change in observed frequency and wavelength of a wave when its source moves relative to an observer.
- How does observed frequency change when a wave source moves towards an observer?
- It increases (and observed wavelength decreases).
- List the electromagnetic spectrum in order of increasing frequency.
- Radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, gamma rays.
- What is true about the speed of all electromagnetic waves in free space?
- They all travel at the same speed in free space (a vacuum).
- Give a use of microwaves and a danger of excessive microwave exposure.
- Use: cooking and satellite transmissions. Danger: internal heating of body tissue.
- Give a use of gamma rays and a danger of excessive gamma ray exposure.
- Use: sterilising food and medical equipment. Danger: cancer and mutation.
- Give a use of ultraviolet radiation and a danger of excessive UV exposure.
- Use: fluorescent lamps. Danger: damage to surface cells and blindness.