Topic 6 - Waves

Question 1

Amplitude

Answer 1

The maximum displacement of a wave from its undisturbed
(equilibrium) position.

Question 2

Angle of Incidence

Answer 2

The angle between the incident ray and normal

Question 3

Angle of Reflection

Answer 3

The angle between the reflected ray and normal.

Question 4

Black

Answer 4

An object will appear black if it absorbs all wavelengths of radiation
incident on it.

Question 5

Colour Filters

Answer 5

Filters that absorb certain wavelengths (colours) and transmit
others. A blue filter for example will absorb all wavelengths other than those in the
blue region of the colour spectrum.

Question 6

Colour

Answer 6

Colour is determined by frequency and wavelength.

Question 7

Constant Temperature:

Answer 7

A body remains at a constant temperature if it is
absorbing radiation at the same rate that it is emitting it.

Question 8

Convex Lens

Answer 8

A lens that brings parallel rays to focus at the principal focus.The
image formed can be either real or virtual.

Question 9

Diffuse Reflection

Answer 9

Reflection from a rough surface that results in scattering

Question 10

Echo Sounding

Answer 10

A technique that uses high frequency sound waves to
detect objects in deep water and to measure the depth of water.

Question 11

Electromagnetic Waves

Answer 11

Transverse waves that transfer energy from the source
of the waves, to an absorber. They form a continuous spectrum of different
frequencies and all travel at the same speed in a vacuum.

Question 12

Focal Length

Answer 12

The distance between the centre of a lens and its principal focus.

Question 13

Frequency

Answer 13

The number of waves passing a given point in a second. It is the
inverse of the wave’s period.

Question 14

Hertz

Answer 14

The unit of frequency.

Question 15

Human Hearing

Answer 15

Humans can hear sounds in the frequency range of 20Hz to 20kHz.

Question 16

Infrared Radiation

Answer 16

A type of radiation that all objects emit and absorb. The hotter
an object is, the greater the infrared radiation it emits in a given time.

Question 17

Infrared

Answer 17

Used for cooking food, electrical heaters and infrared imaging.

Question 18

Ionising Radiation

Answer 18

Radiation that can cause the mutation of genes and cause cancer. X-rays and gamma rays are both forms of ionising radiation.

Question 19

Lens

Answer 19

An object that forms an image through the refraction of light.

Question 20

Longitudinal Waves

Answer 20

Waves with oscillations that are parallel to the direction of travel/energy transfer.

Question 21

Magnification

Answer 21

The ratio of the image height over the object height for a lens.
Since it is a ratio, it has no units.

Question 22

Microwaves

Answer 22

Used for satellite communications and for cooking food.

Question 23

Normal

Answer 23

The normal is an imaginary reference line that is constructed
perpendicular to a boundary at the point that the wave intercepts it.

Question 24

P-Waves

Answer 24

Longitudinal, seismic waves that travel at different speeds
through solids and liquids.

Question 25

Perfect Black Body

Answer 25

An object that absorbs all radiation incident on it and does not reflect or transmit any type of radiation.

Question 26

Period

Answer 26

The time it takes for one complete wave to pass a given point. It is the inverse of frequency.

Question 27

Radiation Dose

Answer 27

A measure of the risk of harm to the body as a result of radiation exposure.

Question 28

Radio Waves

Answer 28

Used for television and radio signals. They can be produced by oscillations in electrical circuits.

Question 29

Reflection

Answer 29

Reflection is when a wave bounces off a boundary. The angle of incidence always equals the angle of reflection.

Question 30

S-Waves

Answer 30

Transverse, seismic waves that cannot travel through liquids.

Question 31

Seismic Waves

Answer 31

Waves that are produced by earthquakes.

Question 32

Sound Waves

Answer 32

The longitudinal waves responsible for sound. In solids, sound waves are transmitted by the vibrations of the solid’s particles.

Question 33

Specular Reflection

Answer 33

Reflection from a smooth surface, in a single direction.

Question 34

Transverse Waves

Answer 34

Waves with oscillations that are perpendicular to the direction of travel/energy transfer.

Question 35

Ultrasound Scanning

Answer 35

A technique that involves ultrasound waves being transmitted and then partially reflected at a boundary before being detected by a detector. The time between transmission and detection can be used to calculate distances, and build up an image.

Question 36

Ultrasound Waves

Answer 36

Waves that have a frequency higher than the upper limit of human hearing (20kHz).

Question 37

Ultraviolet

Answer 37

Used in energy efficient lamps and for sun tanning.

Question 38

Visible Light

Answer 38

The only type of electromagnetic radiation that our eyes can detect. It is used for fibre optic communications

Question 39

Wave Speed

Answer 39

The speed at which energy is transferred through the medium. It is equal to the product of the wave’s wavelength and frequency.

Question 40

Wavelength

Answer 40

The distance from a point on one wave to the same point on the adjacent wave (ie. peak to peak or trough to trough).

Question 41

White

Answer 41

An object will appear white if it emits all wavelengths equally