CHAPTER 11

Question 1

P- WAVES

Answer 1

primary waves- longitudinal waves that travel through the earth from an earthquake

Question 2

S- WAVES

Answer 2

secondary waves- transverse waves that travel through the earth from an earthquake

Question 3

PROGRESSIVE WAVE

Answer 3

a wave where the peaks and troughs, or commissions and rarefactions, move through the medium as energy is transferred

Question 4

LONGITUDINAL WAVE

Answer 4

a wave where the medium is displaced in the same line as the direction of energy transfer- oscillations are parallel to the direction of wave travel

Question 5

TRANSVERSE WAVE

Answer 5

a wave where the medium is displayed perpendicular to the to the direction of energy transfer- the oscillations of medium particles are perpendicular to the direction of wave travel

Question 6

EQUILIBRIUM POSITION (WAVES)

Answer 6

the resting position for particles in the medium

Question 7

RESTORING FORCE

Answer 7

a force that tries to return a system to its equilibrium position

Question 8

PEAK

Answer 8

the maximum positive amplitude of a transverse wave

Question 9

TROUGH

Answer 9

the maximum negative amplitude of a transverse wave

Question 10

COMPRESSONS

Answer 10

a moving region in which the medium is denser or has higher pressure than the surrounding medium

Question 11

RAREFACTIONS

Answer 11

a moving region in which the medium is less dense or has less pressure than the surrounding medium

Question 12

DISPLACEMENT (WAVES)

Answer 12

the distance from the equilibrium position in a particular direction

Question 13

AMPLITUDE

Answer 13

the maximum displacement from the equilibrium position

Question 14

WAVELENGTH

Answer 14

minimum distance between two points in phase on adjacent waves

Question 15

PERIOD OF OSCILLATION

Answer 15

the time taken for one oscillation or time taken for wave to move one whole wavelength past a given point

Question 16

FREQUENCY

Answer 16

the number of wavelengths passing a given point per unit time

Question 17

WAVE SPEED

Answer 17

the distance travelled by the wave per unit time

Question 18

WAVE PROFILE

Answer 18

a graph showing the displacement of the particles in the wave against the distance along the wave

Question 19

IN PHASE

Answer 19

particles oscillating perfectly in time with each other are in phase

Question 20

ANTIPHASE

Answer 20

particles oscillating completely out of step with each other are in antiphase

Question 21

REFLECTION

Answer 21

the change in direction of a wave at a boundary between two different media, so that the wave remains in the original medium

Question 22

LAW OF REFLECTION

Answer 22

the angle of incidence is equal to the angle of reflection

Question 23

ANGLE OF INCIDENCE

Answer 23

the angle between the direction of travel of an incident wave and the normal at a boundary between two media

Question 24

ANGLE OF REFLECTION

Answer 24

the angle between the direction of travel of a reflected wave and the normal at a boundary between two media

Question 25

WAVEFRONT

Answer 25

a line of points in phase with each other i a wave, perpendicular to the direction of energy transfer

Question 26

REFRACTION

Answer 26

the change in direction of a wave as it changes speed when it passes from one medium to another

Question 27

POLARISATION

Answer 27

the phenomenon in which oscillations of a transverse wave are limited to one plane

Question 28

PLANE POLARISED

Answer 28

description of a transverse wave in which oscillations are limited to only one plane

Question 29

UNPOLARISED

Answer 29

description of a transverse wave in which oscillations occur in may planes

Question 30

PARTIALLY POLARISED

Answer 30

description of a transverse wave in which there are more oscillations in one particular plane, but the wave is not completely plane polarised- occurs when transverse waves reflect off a surface

Question 31

INTENSITY

Answer 31

the radiant power passing through a surface per unit area

Question 32

ELECTROMAGNETIC WAVE

Answer 32

transverse waves with oscillating electric and magnetic field components, such as light and X-rays

Question 33

ELECTROMAGNETIC SPECTRUM

Answer 33

the full range of frequencies of electromagnetic waves, from gamma to rays to radio waves

Question 34

RADIO WAVES

Answer 34

long- wavelength electromagnetic waves, with wavelengths greater than 10^-1

Question 35

GAMMA WAVES

Answer 35

short- wavelength electromagnetic waves, with wavelengths from 10^-10 to 10^-16

Question 36

X-RAYS

Answer 36

short wavelength electromagnetic waves, with wavelengths from 10^-8 to 10^-13, which can be used in medical imaging

Question 37

REFRACTIVE INDEX

Answer 37

the refractive index of a material n=c/v

Question 38

TOTAL INTERNAL REFLECTION

Answer 38

the reflection of all light hitting a boundary between two media back into the original medium when the light is travelling through the medium with the higher refractive index and the incidence angle at the boundary is greater than the critical angle

Question 39

CRITICAL ANGLE

Answer 39

the angle of incidence at the boundary between two media that will produce an angle of refraction of 90 degrees