Chapter 9 Waves

Question 1

Wave

Answer 1

transmitter of energy without the movement of particles from place to place. The vibration of particles or energy fields is involved.

Question 2

Transverse Wave

Answer 2

wave involving the vibration of particles perpendicular to the direction of energy transfer

Question 3

Compression Wave / Longitudial Waves

Answer 3

wave involving the vibration of particles in the same direction as energy transfer

Question 4

Medium

Answer 4

material through which a wave moves

Question 5

Vibrations

Answer 5

repeated fast back-and-forth movements

Question 6

Compression

Answer 6

region in which the particles are closer than when not disturbed by a wave

Question 7

Rarefaction

Answer 7

region in which the particles are further apart than when not disturbed by a wave

Question 8

Frequency

Answer 8

number of vibrations in one second, or the number of wavelengths passing in one second

Question 9

Hertz

Answer 9

unit of frequency; its abbreviation is Hz. One hertz is equal to one vibration every second.

Question 10

pITCH

Answer 10

Highness or lowness of a sound. The pitch that you hear depends on the frequency of the vibrating air.

Question 11

Wavelength

Answer 11

distance between two neighbouring crests or troughs of a wave. This is the distance between two particles vibrating in step.

Question 12

Amplitude

Answer 12

maximum distance that a particle moves away from its undisturbed position

Question 13

Sonar

Answer 13

use of reflected sound waves to locate objects under water (sound navigation and ranging)

Question 14

Echolocation

Answer 14

Use of sound to locate objects by detecting echoes

Question 15

Ultrasound

Answer 15

sound with frequencies too high for humans to hear

Question 16

Ear Canal

Answer 16

the tube that leads from the outside of the ear to the eardrum

Question 17

Eardrum

Answer 17

a thin piece of stretched skin inside the ear that vibrates when sound waves reach it

Question 18

Membrane

Answer 18

a thin layer of tissue

Question 19

Auricle

Answer 19

the fleshy outside part of the ear

Question 20

Cochlea

Answer 20

the snail-shaped part of the inner ear. It is lined with tiny hairs that are vibrated by sound and stimulate the hearing receptors.

Question 21

Semicircular Canals

Answer 21

three curved tubes, filled with fluid, in the inner ear that control your sense of balance

Question 22

Auditory Nerve

Answer 22

a large nerve that sends signals to the brain from the hearing receptors in the cochlea

Question 23

Ossicles

Answer 23

a set of three tiny bones that send vibrations from the eardrum to the inner ear. They also make the vibrations larger.

Question 24

Oval Window

Answer 24

an egg-shaped hole covered with a thin tissue. It is the entrance from the middle ear to the outer ear.

Question 25

Relative Intensity

Answer 25

a measure of how loud a sound is using a sound meter

Question 26

Sound Level

Answer 26

the energy of sound that is an indication of the loudness of a sound

Question 27

Decible

Answer 27

a unit of measurement of relative sound intensity

Question 28

Threshold of Hearing

Answer 28

the lowest level of sound that can be heard by the human ear

Question 29

Threshold of Pain

Answer 29

the lowest level of sound that causes pain to the human ear

Question 30

Electromagnetic Spectrum

Answer 30

complete range of wavelengths of energy radiated as electric and magnetic fields

Question 31

Radio Waves

Answer 31

low energy electromagnetic waves with a much lower frequency and longer wavelength than visible light

Question 32

Infa-Red Radiation

Answer 32

nvisible radiation emitted by all warm objects. You feel infra-red radiation as heat.

Question 33

Visible Light

Answer 33

very small part of the electromagnetic spectrum to which our eyes are sensitive

Question 34

Ultraviolet Radiation

Answer 34

invisible radiation similar to light but with a slightly higher frequency and more energy

Question 35

Xray

Answer 35

high-energy electromagnetic waves that can be transmitted through solids and provide information about their structure

Question 36

Gamma Rays

Answer 36

high-energy electromagnetic radiation produced during nuclear reactions. They have no mass and travel at the speed of light.

Question 37

Electromagnetic Waves

Answer 37

electromagnetic energy that is transmitted as moving electric and magnetic fields. There are many different types of electromagnetic energy, e.g. light, microwaves, radio waves.

Question 38

Ray

Answer 38

narrow beams of light

Question 39

Beam

Answer 39

wide stream of light rays, all moving in the same direction

Question 40

Reflection

Answer 40

bouncing off the surface of a substance

Question 41

Luminous

Answer 41

releasing its own light

Question 42

Scattering

Answer 42

describes light sent in many directions by small particles within a substance

Question 43

Transparent

Answer 43

describes a substance that allows most light to pass through it. Objects can be seen clearly through transparent substances.

Question 44

Translucent

Answer 44

allowing light to come through imperfectly, as in frosted glass

Question 45

Opaque

Answer 45

describes a substance that does not allow any light to pass through it

Question 46

Lateral Inversion

Answer 46

reversed sideways

Question 47

Refraction

Answer 47

change in the speed of light as it passes from one substance into another. It usually involves a change in direction.

Question 48

Normal

Answer 48

a line drawn perpendicular to a surface at the point where a light ray meets it

Question 49

Photons

Answer 49

a particle such as a quantum of light or electromagnetism