Topic 6 - Waves

Question 1

What is amplitude?

Answer 1

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

Question 2

What is Angle of Incidence?

Answer 2

The angle between the incident ray and normal.

Question 3

What is Angle of Reflection?

Answer 3

The angle between the reflected ray and normal.

Question 4

What does black mean?

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

What is colour?

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 a 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 wave?

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 a focal length?

Answer 12

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

Question 13

What is a 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 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?

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?

Answer 22

Used for satellite communications and for cooking food.

Question 23

What is a 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

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 a 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?

Answer 28

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

Question 29

What is a 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 is a S- Wave?

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 is a transverse wave?

Answer 34

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

Question 35

What is a ultrasound scan?

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?

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 a 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

What is white?

Answer 41

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

Question 42

What are the two parts of a longitudinal wave called?

Answer 42

Compression and rarefactions.

Question 43

How do sound waves travel through a solid?

Answer 43

The particle sin the solid vibrate and transfer kinetic energy through the material.

Question 44

What technique is used to detect objects in deep water and measure water depth?

Answer 44

- Echo Sounding - High frequency sound waves are emitted, reflected and detected - Time differences between emission and detection, alongside wave speed, are used to calculate distances

Question 45

Order the type of electromagnetic radiation rom lowest to highest frequency.

Answer 45

- Radio waves - Microwaves -Infrared - Visible Light - Ultraviolet - X- rays - Gamma Rays

Question 46

how can radio waves create an alternating current in a circuit?

Answer 46

When radio waves absorbed, they can induce oscillations in a circuit with the same frequency as the wave themselves.

Question 47

What health effects can X- rays and Gamma Rays cause?

Answer 47

- They are ionising radiation so can cause mutations in genes - They can lead to increased risk of developing various cancers

Question 48

What is the difference between the image produced by a convex and a concave lens?

Answer 48

- Convex lenses can produce real or virtual images - Concave lenses can only produce virtual images

Question 49

What determines the colour of an opaque object?

Answer 49

- Different objects reflect different wavelengths of light by different amounts - The wavelength that are most strongly reflected determine the colour

Question 50

Why is a perfect black body the best possible emitter of radiation?

Answer 50

- It is a perfect absorber since it absorbs all radiation incident on it - A perfect absorber is also a perfect emitter

Question 51

Give two factor that affect the temperature of the earth?

Answer 51

- The earth's rate of absorption and emission of radiation - The amount of reflection of radiation into space