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Flashcards in Waves Deck (37):
1

What is frequency

F
How many complete waves per second passing a certain point

Measure in hertz, on hz is one wave per second

2

Amplitude

Height of the wave from rest to crest or trough

Maximum displacement from its equilibrium position

3

Speed of the wave is measured as

Velocity

4

What is the period of a wave

T
Time in seconds for one compete wave to pass a point

5

Measuring frequency of a wave

Frequency = 1 / Time period

6

Wave speed =

Wave speed = frequency x wavelength
M/s Hz. M

Or velocity=

7

Transverse waves examples

Light and other em waves
A slinky wiggled up and down
Ripples

8

What is a transverse wave

A wave with oscillations at 90 degrees to the direction of energy

9

What is a longitudinal wave

A wave that oscillates in the same direction that the energy is moving in

10

Examples of longitudinal waves

Sound
Ultrasound
When you push the end of a slinky

11

All waves can be ...

Reflected refracted and diffracted

12

What is diffraction

When a wave is pushed through a gap it beds round ( obstacles)

The smaller the gad the founder the wave
The longer the wavelength the more it spreads out

13

Law of Reflection

Angle of incidence = angle of reflection

14

When is a wave refracted

When waves travel through a change of density they change speed

15

What happens to a wave when entering a denser medium

It refracts towards the normal as it slows down

16

What happens to a wave when entering a less denser medium

It speeds up and bends away from the normal

17

What happens to light in Prisms

Different colours have different wavelengths are all refracted at different amounts, the waves the emerge the prism with a rainbow effect

18

Different types of em waves in order or increasing frequency and decreasing wavelength

Radio waves -communication, TV and fm radio waves are short
Micro waves-satellites
Infra rd- heat radiation, night vision
Visible light -communication in optical fibres, photographs
Ultra violet - fluorescent lights, the sun cancer,
X Rays - pass through flesh but not denser material, cancer causing
Gamma rays - sterilise instruments and food, van cause cancer

19

What type of waves are em waves

They are all transverse
And travel at the same speed through a vacuumed

20

Order of colour

R ichard
Of
York
Gave
Battle
In
Vain

21

Refractive index=

Refractive index(n) = speed of light in vacuum (c) / speed of light in that material (v)

N = c/v

22

Smells law

Refractive index (n) = sin I / sin r

I is incident Ray
R is refracted Ray

23

What angle is the critical angle in glass

90, when it is reached it travels along the boundary

24

What happens when you get above the critical angle

Total internal reflection

25

Using smells law to find the critical angle

Sin c (critical angle ) = 1 / n ( refractive index)

26

What waves are sound waves, what can they do

Longitudinal
Refract reflect and diffract
They can also be absorbed
The more amps, the louder it is

27

Higher frequency means...

Higher pitch

28

Radio waves in detail

Generated by a transmitter
Received by a areal
They immediately diffract from the transmitter

29

Micro waves in detail

Waves can penetrate atmosphere easily
Transmitted in narrow beams

30

Infra red detail

Heaters and night vision
Or is absorbed by objects and heats them up

31

Damaging em waves

Micro- internal heating of tissue
Infra red- skin burns
Ultra- cells and blindness
Gamma- cancer and mutation

32

Virtual image will be

The same size
Directly opposite object
As far behind as the object is in front
Laterally inverted

33

What are optical fibres

Thin strands of pure glass that is often coated
Total internal reflection takes place
Light is trapped inside
Used for investigating before surgery
Can be flexible

34

What is ultrasound

Used to measure sound
Pulses
Waves are reflected and s map can be produced
Echo sound
Ultra sound scanning

35

Uses of ultrasound

Scanning
Motion sensors
Underwater
Bats

36

What is wavelength

Upside down y called lamda
Distance from one peak to the next

37

Human hearing

20hz to 20,000 hz