P1.5 Waves

Question 1

What are waves?

Answer 1

Made up of many particles. Waves transfer energy from one place to another.

Question 2

What are transverse waves? Give an example.

Answer 2

Waves that move up and down (perpendicular)

Like light or heat waves

Question 3

What are longitudinal waves? Give an example.

Answer 3

Particles that move parallel to the direction of energy transfer.
Sound waves

Question 4

What’s frequency?

Answer 4

The number of waves per second measured in Hertz (Hz)

Question 5

What’s the top of a wave called?

Answer 5

Peak or crest

Question 6

What’s the bottom of a wave called?

Answer 6

Trough

Question 7

What’s the wavelength of a wave?

Answer 7

The distance from peak to peak or tough to trough.

Question 8

What’s the speed of any electromagnetic wave?

Answer 8

3 X 10 to the 8 m/s

Question 9

What’s the amplitude of a wave?

Answer 9

From the middle to the peak/trough of he wave

Question 10

How do you calculate wave speed? Give the units.

Answer 10

Frequency X wavelength

Frequency - Hz
Wavelength - m
Wave speed - m/s

Question 11

What’s the law of reflection?

Answer 11

The angle of incidence = the angle of reflection

Question 12

What are the features of an image produced on a plane mirror?

Answer 12

The same size as the object
The same distance behind the mirror as the object is in front
Upright
Back-to-front compared with the object (lateral inversion)
Virtual

Question 13

What are real images?

Answer 13

They’re formed where light rays cross after reflection by a mirror. They can be cast onto a screen.

Question 14

What are virtual images?

Answer 14

They are formed where light rays only appear to come from. They can’t be cast onto a screen.

Question 15

What is the relationship between the angle of incidence and the angle of refraction?

Answer 15

As the angle of incidence increases so does the angle of refraction. But as it increases the difference between the two angles increases.

Question 16

What happens when light enters a more dense substance?

Answer 16

It slows down and bends towards the normal.

Question 17

What happens when light enters a less dense substance?

Answer 17

It speeds up and bends away from the normal

Question 18

What’s dispersion?

Answer 18

When a spectrum is formed. A prism splits the colours of white light into the spectrum. Red, orange, yellow, green, blue, indigo, violet.
Violet light refracts the most and red the least.

Question 19

What’s diffraction?

Answer 19

The spreading of waves when they pass through a gap or move past an obstacle.
Most diffraction occurs when the gap width is similar to the wave-length of the wave.

Question 20

In diffraction, what happens when the gap is too small?

Answer 20

The waves are reflected by the barrier

Question 21

In diffraction, what happens when the gap is the same size as the wavelength?

Answer 21

Circular waves are produced

Question 22

In diffraction what happens when the gap is bigger than the wavelength?

Answer 22

The waves pass through the gap unchanged apart from a slight diffraction of the waves near their ends.

Question 23

What’s an example of diffraction in day-day life?

Answer 23

Radio waves diffract around the hills to reach houses. Sometimes they don’t diffract enough and this means the tv picture will be fuzzy.

Question 24

What are sound waves?

Answer 24

Vibrations that travel through substances. It consists of a series of compressions and rarefactions.

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Compressions are where the particles are close together and rarefactions are where the particles are far apart.

Question 25

What’s an echo?

Answer 25

A reflected sound

Question 26

What does a bigger amplitude mean?

Answer 26

The loudness increases

Question 27

What happens when frequency increases?

Answer 27

The pitch increases

Question 28

What’s the bell jar experiment?

Answer 28

The bell rings
The air is removed from the bell jar and the sound of the bell ringing becomes quieter until you can’t hear it anymore. This experiment shows that sound cannot travel through a vacuum.

Question 29

What’s the order of the EM spectrum? Starting with the highest frequency.

Answer 29

Gamma
X-Ray's
Ultra-violet
Light
Infrared
Microwaves
Radio

Question 30

What types of waves are EM waves?

Answer 30

Transverse

Question 31

what type of wave can be either transverse or longitudinal?

Answer 31

mechanical

water