A wavelength is the distance from the crest of one wave to the crest of another, measured in metres (m).
The frequency is the number of waves passing any point in one second. This is measured in hertz (Hz).
An amplitude is the greatest displacement of a wave from its undisplaced position. This is measured in metres (m). (Note that amplitude is not the distance between the top and bottom of a wave.)
Wave motion
There are two types of wave motion: transverse and longitudinal. Research these types of waves and compare their characteristics. Use diagrams to support your answer.
Radio wave speed
The speed of a wave can be calculated by multiplying its frequency by its wavelength. If a radio wave has a wavelength of 0.75 m and a frequency of 400 MHz, calculate the speed of this radio wave. Compare your answer to the value for the speed of light in your Formulae and Tables booklet.
Other Waves in Space
Objects in space also give out other types of waves, such as X-rays, gamma rays and infrared radiation. These can be viewed using devices similar to radio telescopes.
These waves cannot get through the Earth’s atmosphere, so the telescopes need to be launched into outer space to receive and understand them.
People and Science
Jocelyn Bell Burnell is an astrophysicist from Northern Ireland. While studying at the University of Cambridge in 1967, she developed a radio telescope under the guidance of her supervisor Antony Hewish. Using this telescope, she discovered the first radio pulsars from outer space.
A pulsar is a fast rotating star that seems to flash brighter and dimmer. Her supervisor was awarded the Nobel Prize in Physics for this discovery. Bell Burnell was not included in the prize, much to the astonishment of the scientific community.
