Waves

What are waves?

• Waves transfer energy from one place to another

What are the differences between transverse and longitudinal waves?

• transverse waves have oscillations that are perpendicular to the direction of energy transfer

• longitudinal waves have oscillations that are parallel to the direction of energy transfer

What do longitudinal waves need?

a medium to travel in e.g air, a liquid or a solid

What do longitudinal waves consist of?

compression and rarefaction

What is the equation for wave speed?

• wave speed= frequency x wavelength

• v = f x λ

What is the equation for the frequency of a wave?

frequency of a wave= number of oscillations/ time taken

What’s the amplitude of a wave?

The maximum displacemnt of a point on a wave away from the undisturbed position

What’s the wavelength of a wave?

the distance from a point on one wave to the equivalent point on the adjacent wave

What’s frequency?

number of waves passing a point each second

What is the symbol for wave speed?

v

What’s the unit for the frequency of waves?

Hertz

What’s the symbol for wavelength?

Lambda

What’s the equation for period?

period= 1/ Freq

Steps to ripple tank practical?

1. measure wavelength by placing a ruler on the paper and freezing image

2. measure distance between 1 wave and 10 waves further

3. Place a timer next to paper and count the number of waves passing a point in 10 seconds and divide by 10 to get the mean freq

4. repeat

What are electromagnetic waves?

transverse waves that transfer energy from the source of the waves to an absorber

Which waves are in the electromagnetic spectrum?

• Radio waves

• Microwaves

• Infrared radiation

• Visible light

• Ultraviolet

• X-rays

• Gamma rays

At the red end of the spectrum the waves have a…

• lower frequency

• longer wavelength

At the violet end of the spectrum the waves have a…

• higher frequency

• shorter wavelength

Only visible light can be detected by the…

human eye

Order of electromagnetic spectrum?

From radiowaves to gamma rays…

• the frequency increases

• wavelength decreases

Electromagnetic waves don’t need a medium to

• travel

• so they can travel through a vacuum e.g space

What happens in refraction?

• waves can change direction when they change speed

• this can happen when moving from one medium from another

What happens when light refracts through a glass balck?

• when light passes from air to glass, the velocity decreases

• causing direction to change so the waves bend towards the normal

• light waves pass through glass block

• when waves pass from glass back to air the velocity increases

If waves enter or leave the medium at right angles ot the surface…

they do not change direction