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Flashcards in Waves Deck (63)
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1

what is a transverse wave?

The oscillations are perpendicular to the direction of energy transfer.
A spring wiggled side to side gives a transverse wave

2

What is a longitudinal wave?

The oscillations are parallel to the direction of energy transfer.
If you push the end of a spring, you get a longitudinal wave.

3

Examples of transverse waves?

-all electromagnetic waves
-ripples and waves in water
- wave on a string
{most waves}

4

Examples of longitudinal waves?

-sound waves in air, ultrasound
-shock waves, seismic waves

5

How do you calculate the wave speed?

Wave speed (m/s) = frequency (Hz) X wavelength (m)

6

What is the frequency of a wave?

The number of complete waves passing a certain point per second. Measured in hertz (Hz)

7

What is the amplitude of a wave?

The maximum displacement of a point on the wave from its undisturbed position.

8

What is the wavelength?

The distance between the same point on two adjacent waves

9

How do you calculate the period of a wave?

The amount of time it takes for a full cycle of waves to pass a point

Period = 1/ frequency

10

What is the angle of incidence?

Angle of incidence = angle of reflection
-the angle between the incoming wave and the normal

11

What is specular reflection?

When a wave is reflected in a single direction by a smooth surface (eg when lit is reflected by a mirror you get a clear reflection)

12

What is diffuse reflection?

When a wave is reflected by a rough surface (eg paper) and the reflected rays are scattered in many different directions

13

What is refraction?

When a wave crosses a boundary between materials at an angle, it changes direction and so it is refracted

14

What is the frequency of a wave?

The number of complete waves passing a certain point per second. Measured in hertz (Hz)

15

What is the amplitude of a wave?

The maximum displacement of a point on the wave from its undisturbed position.

16

What is the wavelength?

The distance between the same point on two adjacent waves

17

How do you calculate the period of a wave?

The amount of time it takes for a full cycle of waves to pass a point

Period = 1/ frequency

18

What is the angle of incidence?

Angle of incidence = angle of reflection
-the angle between the incoming wave and the normal

19

What is specular reflection?

When a wave is reflected in a single direction by a smooth surface (eg when lit is reflected by a mirror you get a clear reflection)

20

What is diffuse reflection?

When a wave is reflected by a rough surface (eg paper) and the reflected rays are scattered in many different directions

21

What is refraction?

When a wave crosses a boundary between materials at an angle, it changes direction and so it is refracted

22

Which rule applies to all reflections?

Angle of incidence = angle of reflection

23

What is an experiment you could do to investigate refraction?

-place rectangular transparent block on a piece of paper and trace around it
-use a ray box or laser to shine a ray of light at the middle of one side of block
-trace the incident Ray and mark where light Ray emerges on the other side of block
-remove block and join up incident Ray and emerging point to show the refracted Ray brought the block

24

Why must you do light experiments in a dim room?

-so you can clearly see the paths of the rays of light
-Ray box and laser means more accurate angle measurements as Ray's can be traced more accurately

25

What is an experiment to investigate reflection and light?

-take piece of paper and draw a straight line across it. Place an object on the line
-shine a ray of light at the objects surface and trace the incoming and reflected light beams
-draw the normal at the point where the Ray hits the object
-use protractor to measure angle of incidence and angle of reflection
-repeat for a range of objects


26

What is an electromagnetic wave?

-transverse waves that transfer energy from a source to an absorber
-they all travel at same speed through air or a vacuum (space)
-they form a continuous spectrum over a wide range of frequencies
-grouped into seven basic types depending on their wavelength and frequency

27

How are radio waves created?

-using an alternating current in an electrical circuit
-object in which charges (electrons) oscillate to create the radio waves is called a transmitter

28

What are uses of EM waves?

Long radio waves- can be transmitted from around the world even if the receiver isn't in sight of the transmitter

Short wave radio waves-can be received at long distances from the transmitter

Bluetooth-uses short wave radio waves
TV/radio- very short wavelengths and you must be in sight of transmitter

29

What is infrared radiation?

Given out by all objects and the hotter the object, the more IR radiation it gives out

30

What do infrared cameras do?

-used to detect infrared radiation and monitor temperature
-it detects IR radiation and turns it into an electrical signal which is displayed as a picture on a screen
-the hotter an object is, the brighter it appears