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. Xrays 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.

Question 42

What is the Acronym for the Electromagnetic Spectrum:

Answer 42

Ronald Macdonald Is Visible Under Xray Glasses

Question 43

Which has a higher frequency, Radio or Gamma:

Answer 43

Gamma