P12/13/14 - Waves

Question 1

What is Amplitude?

Answer 1

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

Question 2

What is the Angle of Incidence?

Answer 2

The angle between the incident ray and normal.

Question 3

What is the Angle of Reflection?

Answer 3

The angle between the reflected ray and normal.

Question 4

When does an object appear black?

Answer 4

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

Question 5

What are 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

How is Colour determined?

Answer 6

Colour is determined by frequency and wavelength.

Question 7

What is 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

What is a 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

What is Diffuse Reflection?

Answer 9

Reflection from a rough surface that results in scattering.

Question 10

What is 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

What are 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

What is Focal Length?

Answer 12

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

Question 13

What is 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

What is Hertz?

Answer 14

The unit of frequency.

Question 15

What is the range of Human Hearing?

Answer 15

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

Question 16

What is 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

What is Infrared used for?

Answer 17

Used for cooking food, electrical heaters and infrared imaging.

Question 18

What is 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

What is a Lens?

Answer 19

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

Question 20

What are Longitudinal Waves?

Answer 20

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

Question 21

What is 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

What are Microwaves used for?

Answer 22

Used for satellite communications and for cooking food.

Question 23

What is Normal in wave context?

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

What are P-Waves?

Answer 24

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

Question 25

What is a 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

What is Period?

Answer 26

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

Question 27

What is Radiation Dose?

Answer 27

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

Question 28

What are Radio Waves used for?

Answer 28

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

Question 29

What is Reflection?

Answer 29

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

Question 30

What are S-Waves?

Answer 30

Transverse, seismic waves that cannot travel through liquids.

Question 31

What are Seismic Waves?

Answer 31

Waves that are produced by earthquakes.

Question 32

What are 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

What is Specular Reflection?

Answer 33

Reflection from a smooth surface, in a single direction.

Question 34

What are Transverse Waves?

Answer 34

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

Question 35

What is 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

What are Ultrasound Waves?

Answer 36

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

Question 37

What is Ultraviolet used for?

Answer 37

Used in energy efficient lamps and for sun tanning.

Question 38

What is Visible Light?

Answer 38

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

Question 39

What is 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

What is Wavelength?

Answer 40

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

Question 41

When does an object appear white?

Answer 41

An object will appear white if it emits all wavelengths equally.