Term 3 Waves (Physics)

Question 1

Define amplitude

Answer 1

The height of the crest or trough in a wave

Question 2

Define frequency

Answer 2

The number of cycles in a wave in a unit of time

Question 3

Define light

Answer 3

A type of energy made of photons that moves as a transverse wave

Question 4

Define a longitudinal wave

Answer 4

Waves where the disturbance moves in the same direction as the wave
The wave moves left to right and at the same time the disturbance moves left to right

Examples a coil spring like a slinky
Sound waves

Question 5

Define sound

Answer 5

Vibrations that move through matter and move as longitudinal waves

Question 6

Define transverse wave

Answer 6

Waves where the disturbance moves perpendicular (at right angles) to the direction of the wave

Wave moves left to right while the disturbance moves up and down
Example ocean wave, Mexican wave of fans in a crowd

Question 7

Define wavelength

Answer 7

The distance between two peaks or two troughs

Question 8

What is a wave

Answer 8

A disturbance that travels through space and matter transferring energy from one place to another

Question 9

What is the highest point of a wave called

Answer 9

The crest

Question 10

What is the lowest point of a wave called

Answer 10

The trough

Question 11

Some every day examples of waves

Answer 11

Sound waves
Microwaves
Radio frequency waves

Question 12

Name 4 properties scientists use describe waves

Answer 12

1. Amplitude - shows strength of wave; measures how much waves moves from the flat or rest position
2. Frequency - number of waves per second. Measures in Hertz or cycles per second
3. Wavelength - distance between two corresponding parts of the wave eg crest to crest (top to top)
4. Speed: time or distance covered by the wave

Question 13

What is a high frequency wave

Answer 13

Waves with high frequency of waves (lots of waves per unit of time)
Shows on a wave graph as more squiggles!

Question 14

What is a low frequency wave

Answer 14

Less peaks and troughs per wave cycle

- less ups and downs on the graph - more spaced out

Question 15

What is a mechanical wave and how do they move

Answer 15

Needs a medium (matter) to travel through
Longitudinal wave
Compressional wave
Transverse wave

Question 16

4 examples of mechanical waves

Answer 16

Sound wave
Seismic wave
Water waves
Ropes and swings

Question 17

What is an electromagnetic wave

Answer 17

Can travel through a vacuum of empty space (don’t need matter to travel through)
Moves in traverse wave
Example if light wave

Question 18

What do both waves types of mechanical waves and electromagnetic waves have in commen?

Answer 18

Both transmit energetic but DO NOT transmit matter

Question 19

What is a SOUND WAVE and how does it start and how does it move ?

Answer 19

Sound wave is a vibration that travels through matter

Vibration starts with a mechanical action eg knock on door pluck guitar string

It travels in longitudinal waves

Question 20

What are the 4 properties of sound?

Answer 20

Loudness - more amplitude means louder (taller waves from the base line)

Pitch - determined by frequency of waves. Higher pitch (high notes) higher frequency
Lept

Timbre - how pure or clear a sound is. One wave type means more pure the note

Echo - bouncing of sound waves off objects and returning to start. Hard materials cause echos while soft materials absorb sound waves

Question 21

What unit do we measure the amplitude fo sound waves in?

Answer 21

Decibels - a loins noise has higher decibels
Human voice is around 60 decibels
Whisper is 20 decibels
Over 120 decibels like a jet plane Up close can damage hearing

Question 22

Why is light unique?

Answer 22

Because it behaves like a particle and like a wave

Question 23

What is the speed of light (the fastest speed in the universe )

Answer 23

3 x 10 to the power of 8 metres per second

That’s why it looks like light is instant when you flick a light switch

Question 24

How is a shadow formed

Answer 24

When an object blocks light
The more solid the object the darker the shadow is formed.
If an object is transparent it will let light through so have a pale shadow

Question 25

How do shadows change shape

Answer 25

Depends on the position of the light source

Lower sun in sky gives longer shadow

Question 26

What makes light reflect off a surface

Answer 26

If the object is shiny it means it is reflecting light

Question 27

What is the angle of reflection

Answer 27

The angle that light reflects off a surface

Flat surface means light hits the surface and is reflected away at the SAME angle
Example a mirror

Question 28

What is an incident ray?

Answer 28

It’s reflected rays