Waves

Question 1

refraction

Answer 1

the change in direction of a wave,
when passing from one medium to another due
to a change in speed of the wave

Question 2

why does refraction occur

Answer 2

• light waves slow down when entering a more optically dense medium
• leading edge of a wave hits the boundary and slows down
• trailing edge of the wave still travels at the same speed
• the front changes direction

Question 3

snell’s law

Answer 3

sin(angle of incidence) / sin(angle of refraction)
to find refractive index

Question 4

what affects a material’s ability to refract light

Answer 4

optical density and refractive index

Question 5

when does light reflect off of the boundary rather than refracting through it

Answer 5

• when the angle of incidence is greater than the critical angle
• when passing from a more optically dense medium to a less optically dense medium

Question 6

what happens if the angle of incidence is equal to the critical angle

Answer 6

• the ray of light will refract along the boundary

Question 7

what is the critical angle

Answer 7

smallest angle of incidence that Total Internal Reflection can occur

Question 8

total internal reflection

Answer 8

• angle of incidence > critical angle
• all light is internally reflected
• core is more optically dense than air

Question 9

sin(critical angle) =

Answer 9

1 / n

Question 10

uses of total internal reflection

Answer 10

• endoscopies
• communication (higher bandwidth)
• periscope

Question 11

when can light refract out of a material

Answer 11

if it hits less than the critical angle

Question 12

transverse waves

Answer 12

vibrations move perpendicular to the wave
light waves

Question 13

what is a wave

Answer 13

transfer of energy without the total transfer of matter

Question 14

longitudinal waves

Answer 14

vibrations move parallel to the wave
sound waves

Question 15

wavelength

Answer 15

length of an entire wave from one point on the wave to the next identical point on the wave

Question 16

amplitude

Answer 16

distance from the middle point to the high point of a wave

Question 17

peak

Answer 17

very top of the wave

Question 18

trough

Answer 18

very bottom of the wave

Question 19

displacement

Answer 19

how far above or below the equilibrium
point a point on a wave is

Question 20

higher pitched noises

Answer 20

have shorter wavelengths

Question 21

louder noises

Answer 21

have taller amplitudes

Question 22

relationship between tension and frequency

Answer 22

increasing the tension (on a string) increases the frequency (higher pitch)

Question 23

the doppler effect

Answer 23

the change in the frequency of a wave in relation to an observer

Question 24

change in wavelength / reference wavelength

Answer 24

velocity of object / speed of wave

Question 25

wavelength further away from observer

Answer 25

longer

Question 26

frequency of shorter wavelenths

Answer 26

higher frequency

Question 27

Why are different colours of light different

Answer 27

each colour has a different wavelength **red** longest **violet** shortest

Question 28

How did scientists find out about invisible types of wave

Answer 28

light passed theough a glass prysm - Dark side of the moon

Question 29

frequency of colours

Answer 29

**violet** - highest **red** - lowest

Question 30

what colour carries more energy

Answer 30

violet

Question 31

electromagnetic spectrum

Answer 31

**LONGEST WL** * * radiowaves * * microwaves * * infrared * * visible light * * ultraviolet * * x-rays * * gamma rays **SHORTEST WL**

Question 32

uses of radiowaves

Answer 32

for communication, broadcast of television and radio, satellite transmissions

Question 33

uses of microwaves

Answer 33

communication links, wireless networks, microwave radio relay networks, radar, satellite and spacecraft communication

Question 34

uses of infrared waves

Answer 34

electrical heaters, cookers, short-range communications (remotes), security systems, thermal imaging cameras

Question 35

uses of visible light waves

Answer 35

photography and illumination

Question 36

uses of ultraviolet waves

Answer 36

sunbeds

Question 37

uses of x-ray waves

Answer 37

detects bone fractures, certain tumors, other abnormal masses

Question 38

uses of gamma rays

Answer 38

medicine, industry (sterilization and disinfection), the nuclear industry

Question 39

dangers of ultraviolet, x and gamma rays

Answer 39

they can damage/kill cells within the body

Question 40

properties of x-ray waves

Answer 40

* have a shorter wavelength * capture defects in skeleton * travel in a straight line - do not carry an electric charge * can travel in a vacuum.

Question 41

ultrasound

Answer 41

sound waves with a frequency higher than 20,000Hz - higher than the human range

Question 42

uses of ultrasound

Answer 42

* pest control * view the uterus during pregnancy * physiotherapy

Question 43

period

Answer 43

time taken for one full oscillation

Question 44

frequency =

Answer 44

1 / period

Question 45

how can sound waves be represented

Answer 45

using an oscilloscope