11 Progressive Waves

Question 1

Similarities between secondary and primary waves

Answer 1

Both are progressive waves

Question 2

Differences between primary and secondary waves

Answer 2

Primary waves are longitudinal
Secondary waves are transverse

Question 3

Progressive wave

Answer 3

An oscillation that travels through matter. They transfer energy but not matter

Question 4

Displacement (wave)

Answer 4

Distance from the equilibrium position in a particular direction

Question 5

Amplitude

Answer 5

Maximum displacement from the equilibrium position

Question 6

Wavelength

Answer 6

The distance between two points on adjacent waves

Question 7

Period of oscillation

Answer 7

The time taken for one oscillation to move one whole wavelength past a given point

Question 8

Frequency

Answer 8

The number of wavelengths passing a given point per unit time

Question 9

Wave speed

Answer 9

The distance travelled by the wave per unit time

Question 10

v = f lambda

Answer 10

Wave speed = frequency x wavelength

Question 11

f = 1/T

Answer 11

Frequency = 1/ period

Question 12

In phase

Answer 12

Particles which oscillate perfectly in step with one another

Question 13

Law of reflection

Answer 13

The angle of incidence is equal to the angle of reflection

Question 14

Refraction

Answer 14

When a wave changes direction as it changes speed when it passes from one medium to another. This changes wavelength wave speed but not frequency

Question 15

Meaning of FAST

Answer 15

Fast
Away
Slow
Towards

Question 16

Diffraction

Answer 16

When a wave passes through a gap or travel around an obstacle they spread out. This does not changes speed frequency or wavelength

Question 17

Polarisation

Answer 17

The particle oscillate along in one direction only. The wave is confined to a single plane. Longitudinal waves can not be polarised

Question 18

Partial polarisation

Answer 18

When a transverse wave reflects off a surface

Question 19

Intensity

Answer 19

The radiant power passing through a surface per unit area

Question 20

I = P/A

Answer 20

Intensity = Power / Area (4 pi r^2)

Question 21

What is the relationships between intensity and amplitude

Answer 21

Intensity is directly proportional to amplitude squared

Question 22

What are electromagnetic waves

Answer 22

Magnetic fields oscillating at right angles to each other

Question 23

Wavelength of radio waves

Answer 23

X>10^-1

Question 24

Wavelength of microwaves

Answer 24

10^-1 >x> 10^-3

Question 25

Wavelength of infrared

Answer 25

10^-3 >x> 7x10^-7

Question 26

Wavelength of Visible light

Answer 26

7x10^-7 >x> 4x10^-7

Question 27

Wavelength of ultraviolet light

Answer 27

4x10^-7 >x> 10^-8

Question 28

Wavelength of x rays

Answer 28

10^-8 >x> 10^-13

Question 29

Wavelength of Gamma rays

Answer 29

10^-10 >x> 10^-16

Question 30

What is the speed of light in a vacuum

Answer 30

3x10^8

Question 31

What is the order of electromagnetic wave

Answer 31

Radio waves Microwaves Infrared Visible Ultraviolet X rays Gamma rays

Question 32

What is the benefit of polarising electromagnetic waves

Answer 32

Reduce interference

Question 33

n = c/v

Answer 33

Refractive index = speed of light in a vacuum / speed of light through the material

Question 34

n sin (theta) = k

Answer 34

Refractive index x sin (angle of incidence) = constant

Question 35

Total internal reflection

Answer 35

When light strikes a boundary at a larger angle to the normal and the light is reflected back into the original medium

Question 36

Conditions for TIR

Answer 36

Light must be travelling through a medium with a higher refractive index The angle at which the light strikes the boundary must be above the critical angle

Question 37

n sin(C) = sin(90)

Answer 37

Refractive index x sin(critical angle) = 1