Light and Sound Topic test Y8

Vacuum

A space with no matter, including air.

Amplitude

The height of a wave from the rest position.

Frequency

The number of waves passing a point per second.

Reflection

Occurs when light bounces off a surface.

Refraction

The bending of light as it passes through different materials.

Transmission

When light passes through a material.

Opaque

A material that does not let light through.

Translucent

A material that lets some light through but not clearly.

Transparent

A material that allows most light to pass through clearly.

Light wave

An example of a transverse wave is a…

eg. Sound wave

An example of a longitudinal wave is a…

Electromagnetic spectrum

Light waves and radio waves are part of this spectrum.

Gamma radiation

Part of the electromagnetic spectrum with highest energy and frequency.

Compression

Part of a sound wave where particles are closer together. On a wave graph, it is represented by a high point, or crest.

Decibel

A unit used to measure loudness.

Hearing range

The range of frequencies that can be heard by a human or animal. Humans: about 20 Hz to 20,000 Hz.

Hertz

The standard unit of frequency (i.e. waves per second).

High‑pitched

The quality of sounds produced by waves with high frequency.

Longitudinal wave

A wave in which particles move back and forth (parallel) in the same direction as the wave.

Loud

The quality of sounds produced by waves with high amplitude.

Loudness

A quality of sound that depends on the amplitude of the sound wave.

Low‑pitched

The quality of sounds produced by waves with low frequency.

Medium

A substance that a wave travels through such as air, water, and solids.

Pitch

A quality of sound that depends on the frequency of the sound wave.

Quiet

The quality of sounds produced by waves with low amplitude.

Rarefaction

Part of a sound wave where particles are further apart. On a wave graph, it is a low point, or trough.

Sound

A type of energy transmitted by vibrating particles. It travels through solids, liquids and gases but not through a vacuum.

Sound wave

A vibration of particles that transfers energy, e.g. ringing bell, vocal cords.

Transverse wave

A wave in which particles move at right angles (perpendicular) to the wave direction. E.g. ocean waves.

Wave

A repeated motion that transfers energy.

Wavelength

The distance between one crest of a wave and the next crest.

Absorption

The transfer of light energy into an object.

Colour

A property of visible light that depends on its frequency.

Concave lens

A lens curved inwards and thinner in the middle; it causes light rays to diverge and produces smaller images.

Converge

To come together; convex lenses cause parallel light rays to…

Convex lens

A lens curved outwards and thicker in the middle; it causes light rays to converge and produce magnified images

Diverge

To spread apart; concave lenses cause parallel light rays to ...

Focal length

Distance from the centre of a lens to its focal point; depends on the strength of refraction.

Focal point

The point where light rays converge (convex) or appear to diverge from (concave).

Lens

A curved, transparent object (glass/plastic) that refracts light. Used in glasses, microscopes, etc.

Light

A type of energy that travels in electromagnetic waves. Enables vision and powers photosynthesis.

Magnification

How much larger a lens makes an image.

Period

The time it takes for one complete wave cycle.

Periodic motion

Repeated motion at regular intervals.

Prism

A transparent object with flat surfaces that refracts light and shows that white light contains all colours.

Visible spectrum

Range of light frequencies visible to humans. Includes all colours of the rainbow.

0°

What is the angle for a longitudinal wave?

90°

What is the angle for a transverse wave?

Because it reflects green wavelengths of light and absorbs others, particularly red and blue wavelengths, due to its pigmentation.

Why is a grape green?

A microscope is used to magnify small objects, typically used for viewing things that are close up. Whist a telescope is used to magnify distant objects.

What are the differences between a microscope and a telescope?

In a solid rock sound waves travel fast due to the density of the medium.

In a lake/water sound travels slower in water than in solid rock but faster than in air.

In air sound travels slowest in air due to its lower density.

From solid rock to a lake to air, how will sound waves flow?

Eyeglasses, door peepholes, laser beams in scanners, and medical equipment.

What is a concave lens used for

Cameras, microscopes, telescopes, and projectors

What is a convex lens used for