S-Cool Revision Summary

S-Cool Revision Summary

Sound waves are caused by particles vibrating. The frequency of the vibration decides the pitch of the sound. The amplitude of the vibrations decides the loudness of the sound.

Ultrasound waves are high frequency sound waves, which are beyond the human hearing range. Ultrasound is used for seeing babies in the womb, detecting cracks in metal and cleaning instruments.

Waves can be represented on an oscilloscope screen, which can be used to measure the characteristics of the waves. You should be able to find the amplitude and time period of a wave from an oscilloscope screen.

The electromagnetic spectrum is a series of waves that all travel at the same speed in a vacuum. They are all transverse. Each part of the spectrum has different uses and dangers. Each part of the spectrum has a different frequency and wavelength. Gamma waves are at the high frequency end of the spectrum. Radio waves are at the low frequency end. You will need to know the uses and dangers of each part of the spectrum.

Different surfaces and materials absorb different frequencies of waves. White surfaces reflect most waves. Black surfaces absorb most waves.

Information can be carried along copper cables as electrical signals, or along optical fibres as electromagnetic wave pulses.

Optical fibres have advantages over copper cables. Optical fibres can carry more information, the signals can travel faster and lose less energy as they travel along the cable.

There are two types of signals, analogue and digital. Analogue signals have a continuous range of values. Digital signals have only two values, on (1) and off (0).

Digital signals have advantages over analogue signals. Digital signals are easier to transmit as they are less affected by noise, it is also possible to send more information, in a certain time, as a digital signal than as an anologue signal.