Friday, 30 March 2018

Section 3 d) Key Words

Amplitude: The distance between the crest of a wave and the neutral point 0. Larger amplitudes mean louder sounds (in sound waves)

Analogue signal: A signal that continuously varies. It is easily distorted and difficult to restore.

Angle of incidence: The angle at which a wave changes from one medium to another, compared to the normal.

Angle of refraction: The angle at which a wave is refracted from the perpendicular surface.

Bandwidth: The frequency of a wave. Digital signals have wider bandwidths, meaning they can carry more information at once.

Critical angle: The angle at which the wave is no longer refracted, but changes to becoming reflected.

Diffraction: When a wave passes an object and spreads beyond it. Its effect is affected by the wavelength in proportion to the size of the gap/blockage. If the gap is smaller in proportion to a larger wavelength, the effects of diffraction are greater.

Digital signal: A signal with only two settings, 0 and 1. It is easily restored and has a larger bandwidth than an analogue signal, so it is able to carry more information.

Frequency: How many times a wave is completed in one second.

Longitudinal waves: Waves that oscillate in the direction of travel. Sound waves are longitudinal.

Oscillation: The vibration. One wave.

Oscilloscope: A machine that measures the vibrations of a wave and creates a trace.

Pitch: How high or low a sound is. A flute makes a high-pitched noise, whereas a double bass makes a low-pitched noise.

Plane mirror: A completely flat mirror.

Reflection: When waves bounce off a surface they are reflected.

Refraction: The change in direction of waves after passing from one medium to another.

Refractive index: The refractive index of a medium tells us how much it will refract light waves. It can be found by this formula: n = sin i / sin r

Total internal reflection: When all waves are reflected inside a medium, none are refracted.

Transverse waves: Waves that oscillate perpendicular to the direction of travel. Light waves are transverse.

Virtual image: An image that is not real, it is a projection or reflection.

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Section 4 b) Summary

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