waves

waves

Types of wave

• Mechanical waves: Produced by a disturbance - (vibrating object) waves are transmitted by the particles of the object

• Progressive waves: carries energy from one place to another without transferring matter. Transverse & Longitudinal waves

Transverse waves

• direction of the wave disturbance (wave pattern) is at right angles to the direction the wave is travelling.

• ripples on top of water

• secondary waves of an earthquake

• ocean waves

• Light

Displacement Distance graphs

• Shows a point in time

• Distance moved of the wave

• From the original position - cause of the wave.

Wavelength

• Greek letter λ (lambda)

• distance between the crests

Frequency

• Frequency - ƭ

• Number of complete waves generated each second.

Speed

• Speed; v, is the distance moved in the direction of travel in 1 second

Amplitude

• Amplitude: a, is the height of the crest of a wave, or the depth of a trough.

• This is measured from the undisturbed position of what is carrying the wave. (the straight line)

Phase

• Points at the times 0, 2, 4, and 6 are called the phases.

• This show the direction of the wave.

• 0 and 4 will have the same speed in the same direction and are in phase

• 2 and 6 are also in phase but out of phase with 0 and 4 because they are travelling in opposite directions.

Fill in the Blanks

what is the height of a wave called?

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What is the number of each wave passing a point in each second called?

Multiple Choice

What are the points labelled A through to E called?

• Hertz

• Phases

• Amplitude

• speed

Multiple Choice

Which 3 points are 'in phase'?

• 0, 4, 8

• 0, 2, 4

• 2, 4, 6

• 0, 4, 6

Wave Equation

• speed = frequency x wavelength

• v = f x λ

• speed - metres per second

• frequency - Hertz

• wavelength - usually metres

Fill in the Blanks

1.The speed of a wave with a frequency of 1650 Hz and a wavelength of 0.2 m.

Fill in the Blanks

2.The speed of a wave with a frequency of 550 Hz and a wavelength of 0.6 m.

Fill in the Blanks

3.The frequency of a sound wave with a wavelength of 0.01 m travelling at 330 m/s.

Fill in the Blanks

4.The wavelength of a sound wave with a frequency of 1.5 kHz (is this the right unit?) travelling at 330 m/s.

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(image shows 1 second). What is the frequency of this wave? (include units)

Frequency can also be calculated by time period

frequency = 1/ time

Fill in the Blanks

Calculate the frequency of:

1.Time period = 0.1 s

Fill in the Blanks

Calculate the frequency of: 2.Time period = 0.5 s

Fill in the Blanks

Calculate the frequency of: 3.Time period = 0.2 s

Light

• Light is a transverse wave

• objects that make their own light are called luminous

• Luminous sources radiate light when when their atoms become excites as a result of receiving energy.

Before we move to lens'

• Reflection

Reflection (on a plane mirror)

• i = r

• angle of incidence will always be the same as angle of reflection

• 
  

Move to powerpoint

You will need paper, ruler and a sharp pencil

Multiple Select

A real image: select the TWO correct statements.

• Can be projected onto a screen because light actually passes through the point where the image appears

• cannot be projected

• Always inverted

• Image only seems to be there

Multiple Choice

Which Lens?

• Concave

• Convex

Multiple Choice

Which lens?

• Concave

• Convex

Multiple Choice

Which lens causes light rays to converge?

• concave

• convex

Multiple Choice

Which lens cause light rays to diverge?

• concave

• convex

Multiple Choice

Is this image...

• Real

• Virtual

Multiple Choice

Is this image....

• Real

• Virtual

Multiple Choice

Which lens causes light rays to converge?

• concave

• convex