Energy Transfer and Communication

Question 1

What is the particle model of matter?

Answer 1

• Particles are constantly moving
• All matter is composed of particles
• When you cool down matter, the particle bonds will grow closer, forming a solid.
• When you heat up matter, the particles bonds weaken, forming a liquid or gas

Question 2

What is conduction?

Answer 2

The transmission of heat via contact from matter to matter, particle to particle.

Question 3

What is convection?

Answer 3

Convection occurs in the form of convection currents. In the example of water, warm water is less dense and rises. It is replaced with denser, cooler water.

Question 4

What do waves carry?

Answer 4

Waves are carriers of ENERGY.
As waves travel through a medium, they lose energy.

Question 5

Explain longitudinal waves in terms of compression and refraction.

Answer 5

Longitudinal waves move through compression and refraction. In refraction, they’re forced apart, and in compression, they’e forced together.
The energy in the wave disturbs the first particle in the medium, which will disturb the second and so on.

Question 6

Draw a longitudal wave with labels.

Answer 6

||| | | | ||| | | |
*compression
*rarefraction

Question 7

Explain transverse waves in terms of it’s properties.

Answer 7

FREQUENCY -
Number of waves passing a fixed point in a given amount of time. It’s measured in HERTZ and the symbol is (f)

PERIOD -
amount of time it takes for one wave to occur. Measured in SECONDS.

Wavelength -
Distance between the top of one wave and the next wave. It’s often measured in METRES

Amplitude -
Distance between undisturbed position of the wave and it’s peak. Measured in METRES

Crest -
Peak of wave

Trough -
Lowest part of wave

Wave Height -
Distance between crest and trough

Question 8

Draw a transverse wave with labels.

Answer 8

~~~~~~~~~~
*Amplitude
*Wavelength
*Frequency
*One wave
*Crest
*Trough
*Wave height

Question 9

Distinguish between transverse and longitudinal waves.

Answer 9

Transverse waves move perpendicular to the direction of the wave, whereas longitudinal move parallel

Question 10

Explain how different mediums affect the transmission of sound.

Answer 10

Sound is a longitudinal wave, meaning it requires particles to be disturbed.
Based off this logic, sound travels fastest in solids, where particles are more dense.
This why a vacuum (empty space) is silent, and why it’s easier to hear through walls than across a field.

*When temp increases, the speed of sound increases

Question 11

Describe the relationship between frequency and pitch

Answer 11

High frequency = higher pitch of sound

Question 12

Describe the relationship between amplitude and volume.

Answer 12

larger amplitude = larger volume

Question 13

Outline all the waves on the electromagnetic spectrum.

Answer 13

Radio waves
Micro waves
Infared waves
Visible Light
Ultra violet waves
X Rays
Gamma Rays

Radio -> Gamma is increased frequency.
Gamma -> Radio is increased wavelength

Question 14

Describe movement of light through a vacuum.

Answer 14

Light travels through a vacuum, whereas sound CANNOT.

Question 15

State the law of reflection.

Answer 15

The ANGLE OF INCIDENCE = ANGLE OF REFLECTION.
Find the angle of incidence using
90 degrees - given angle

Question 16

Draw and label a diagram demonstrating the law of reflection.

Answer 16

N/A

Question 17

Name all the labels in a law of reflection diagram.

Answer 17

*Incident ray
*angle of incidence
*normal
*angle of reflection
*reflected ray
*mirror
*point of incidence

Question 18

How is an image formed in a plane mirror?

Answer 18

*The size of the image is the same as the physical object
*The image is erect (right side up)
*The image is laterally inverted
*The image appears “behind” the mirror

Question 19

Define refraction.

Answer 19

The bending of light rays in response to the density of a medium.

Question 20

Explain the use of refraction in optical instruments.

Answer 20

By adjusting the thickness of glasses, the focal point changes because there is more or less refraction. This means the light can be directed onto the retina properly.
More longsighted = more convex
Shortsighted = concave

Question 21

Draw a diagram demonstrating refraction.

Answer 21

N/A

Question 22

Name all the labels in a refraction diagram.

Answer 22

*Two different mediums
*Incident ray
*Refracted ray
*Angle of incidence
*Angle of refraction

Question 23

Identify what white light is made up of.

Answer 23

All of the colours.

Question 24

Explain the appearance of coloured objects.

Answer 24

An object appears a certain colour because it will absorb all colours of light rays except the colour it is. This ray is then reflected and we see it appear a certain way.

Question 25

Give examples of uses of electromagnetic radiation.

Answer 25

Radio = radio stations Micro = microwaves Infared = reveals objects in space that can't be seen with visible light Visible light = only part of the EM spectrum the eye can see; sight UV waves = cures ink and resin, kills bacteria, suntanning X-Ray = detect breaks and fractures. Gamma Rays = radiotherapy and used to sterilize medical instruments.

Question 26

What direction does the medium move in a longitudinal wave?

Answer 26

It moves PARALLEL to the direction of the wave.

Question 27

What direction does the medium move in a transverse wave?

Answer 27

Perpendicular to the direction of the wave.

Question 28

How do images appear in convex mirrors?

Answer 28

*Image is virtual *Image is erect *Image formed is SMALLER than the real object *Image is inverted

Question 29

How do images appear in concave mirrors

Answer 29

*Image is REAL *Image is magnified (the image is not real when it's magnified) *Image gets smaller the further you go from the mirror, which is what generates the real image

Question 30

Draw diagrams demonstrating light reflecting off plane, convex and concave mirrors.

Answer 30

N/A

Question 31

What is "focal length"

Answer 31

Distance between mirror and focal point.

Question 32

Where is the focal point in convex and concave mirrors?

Answer 32

Convex = behind the mirror Concave = in front of the mirror

Question 33

What is the focal point?

Answer 33

Where light rays converge.

Question 34

Define absorption

Answer 34

Light is absorbed by a median and converted to chemical energy.

Question 35

Define reflection

Answer 35

Waves encounter a boundary where absorption cannot occur, and the waves are bounced off

Question 36

Define efraction

Answer 36

The bending of light as it enders from one medium to another, causing it to speed up or slow down.

Question 37

What determines which way light bends?

Answer 37

Density of new medium. Low density -> high density = bends TOWARDS normal High density -> Low density = bends AWAY from normal

Question 38

What do white surfaces reflect?

Answer 38

All colour.

Question 39

What do black surfaces reflect?

Answer 39

No colour. They absorb all colour.

Question 40

How do you know the size of an angle in a refracted ray?

Answer 40

If it’s going from a low density to high density, it will be LARGER than the angle of incidence. If it’s going from a high density to low density, it will be SMALLER than the angle of incidence. *check with sir*