Unit 3: Waves

Question 1

What is Amplitude?

Answer 1

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

Question 2

What is the Critical Angle?

Answer 2

The angle of incidence which produces an angle of refraction of 90 degrees

Question 3

What is the Doppler Effect?

- Change
- Observed ( , )
- Relative

Answer 3

The change in a wave’s observed wavelength and frequency when there is relative motion between its source and an observer.

Question 4

What is the Electromagnetic Spectrum?

Answer 4

A group of transverse waves that cover a large range of frequencies and wavelengths.

Question 5

What is Frequency?

Answer 5

The number of waves passing a given point in a second.

Question 6

What are Gamma Rays?

Answer 6

High energy radiation rays used for detecting and treating cancers, and sterilising food and medical equipments. They can cause cell damage and mutations.

Question 7

What is Hertz (Hz)?

Answer 7

The unit of frequency.

Question 8

What is Infrared Radiation?

Answer 8

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 9

What is Infrared used for?

Answer 9

Used for cooking food, thermal imaging and short range communications. It can cause skin burns.

Question 10

What is the Law of Reflection?

Answer 10

The angle of incidence must always equal the angle of reflection when a wave reflects.

Question 11

What are Longitudinal Waves?

Answer 11

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

Question 12

What are Microwaves used for?

Answer 12

Used for satellite communications and for cooking food. They can cause internal heating of body cells.

Question 13

What are Radio Waves used for?

Answer 13

Used for television, broadcasting, communications and radio signals.

Question 14

What is Refraction?

- Speed
- Direction
- Medium

Answer 14

The changing of speed, and consequently the direction of a wave as it changes medium. The wavelength of the wave will also change but the frequency remains constant.

Question 15

What is the Refractive Index?

Answer 15

The ratio of the speed of the wave in a vacuum to the speed of the wave in a given medium.

Question 16

What are Sound Waves?

Answer 16

The longitudinal waves responsible for sound. They require a medium to travel through and are transmitted by the vibrations of the medium’s particles.

Question 17

What is the Speed of EM Waves?

Answer 17

All electromagnetic waves travel at the same speed in a vacuum.

Question 18

What is the Time Period?

Answer 18

The time it takes for one complete wave to pass a given point.

Question 19

What is Total Internal Reflection?

Answer 19

When all of a wave is reflected when it meets a boundary. It occurs when the angle of incidence is greater than the critical angle, and only when going from a higher refractive index (optically denser material) to a lower one.

Question 20

What is Ultraviolet used for?

Answer 20

Used in fluorescent lamps, disinfecting water, and for sun tanning. It can cause cell and eye damage that can result in skin cancer and eye conditions.

Question 21

What is Visible Light?

Answer 21

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

Question 22

What is a Wave?

Answer 22

A process of energy transfer through oscillations, without matter being transferred with it.

Question 23

What is Wavelength?

Answer 23

The distance between a point on one wave & the same point on the next wave.

Question 24

What are X-Rays used for?

Answer 24

Used for medical imaging and security scanners. They can cause cell damage and mutations.