# P1 Revision Cards

HideShow resource information
• Created by: timz16
• Created on: 18-05-16 18:02
Whats the difference between heat and tempreture, and what is each measured in?
Heat is measurement of energy and is measured in joules and Tempreture is a measure of hotness which can be measured in degrees celsuis and degrees fahrenheit
1 of 49
What is Specific heat capacity?
How much energy a substance can store or how much energy is needed to raise 1kg of a substance by 1 degrees celsuis
2 of 49
What is Specific latent heat?
Is the energy needed to change state or the amount of energy needed to melt/boil 1kg of a substance without changing its tempreture
3 of 49
What is the formula for Specific heat capacity?
Energy = mass x Specific heat capacity x Tempreture change
4 of 49
What is a formula for Specific latent heat?
Energy = mass x Specific latent heat
5 of 49
Explain why heating a pan of boiling water does not increase its tempreture
Because when a substance is melting/boiling energy is still being put into it but instead the energy is used for breaking intermolecular bonds rather than raising the tempreture
6 of 49
Define conduction?
conduction is where vibrating particles pass on their extra kinetic energy to other neighbouring particles
7 of 49
Define convection?
convection is where energetic particles move from the hotter region to the cooler region - taking their heat energy with them
8 of 49
Explain how radiation is different to conduction and convection?
Does not need a medium to happen so it can occur through space, It can only occur through transparent objects and the amount of radiation emitted or absorbed depends on the colour and texture of object.
9 of 49
Explain how grills and toasters cook food?
Heat is radiated by the device and is absorbed by the surface particles of the food - from here it is convected or conducted to more central parts
10 of 49
Explain how a Microwave cooks food?
Microwaves are produced by a microwave which oenetrate about 1cm deep into the outer layer of food where they're absorbed by water or fat molecules. then the enrgy is conducted of convected to other parts.
11 of 49
What is a thermogram?
a picture taken with a thermal imaging camera and can be used to show whether an object is hot or cold.
12 of 49
List 6 ways you can insulate your home to reduce conevection or conduction?
Thick curtains, double glazing, draught proofing, Cavity walls & Insulation, Loft insulation and Hot water tank jacket
13 of 49
Write down the formula for Effeciency?
Useful Energy Output / Total Energy Input X 100
14 of 49
What does the tickness of an arrow mean on a Sankey diagram?
The more energy it represents
15 of 49
What is the amplitude, wavelength and Frequency of a wave?
ampliture is the displacemnt from rest position to the crest. Wavelength is length of a full cylce of the wave and frequency is the number of oscillations passing each second
16 of 49
Write the formula for calculating the speed of a wave?
Wave Speed = Frequency x Wavelength
17 of 49
Explain how a wave can be totally internally reflected?
A wave hitting a surface can experience total internal reflection, and if the angle of incidence is big enough (than the critical angle) the way doesn't come out at all but reflects into the material
18 of 49
Briefly describe what happens to a wave when its diffracted and and refracted?
Diffraction is when the wave spreads out and depends on the size of the wavelength relative to the obstacle/gap. (If the gap is the same as the wavelength you get maximum diffraction) Refraction is when the speed of a wave can change its direction.
19 of 49
List seven types of electromagnetic waves in order of wavelength?
Radio waves, Microwaves, Infra Red, Visible Light, Ultra Violet, X Rays and Gamma Rays
20 of 49
What is an advantage and Disadvantage of using optical fibres rather than radio signals?
Advantage is that they are secure and cannot be tapped into, where as radio signal can be intercepted since they pass through the ait. Disadvantage is that optical fibres are difficult to repair if damaged
21 of 49
Explain why Morse Code is a digital signal?
because the light pulses are only either 'off' or 'on' - the principle behind morse code was that off and on signal could be relayed over long distances to communicate
22 of 49
What are some of the Advantages of using Light?
very quick way to communicate and theres little interference (digital signal)
23 of 49
Explain how light signals can travel through optical fibres.
When the ray of light enters the optical fibre it hits it at an angle greater than the critical angle. (material) This causes total internal refelection and the light ray is reflected again and agin until it emerges at the other end
24 of 49
Explain why Lasers are thought to be 'monochromatic'?
all the waves are at the same frequency
25 of 49
Explain why the beam of a laser is said to 'intense'?
The light waves are all in phase with each other
26 of 49
Why are waves said to be coherent?
Because they have a fixed phase difference
27 of 49
A Laser is said to have a low divergence, what does this mean?
The beam is narrow and stays narrow even at long distances
28 of 49
Briefly describe how CD players use lasers to read digital information?
the surface of a CD contains land and pits. When a laser beam is shone onto the lands and pits it can be picked up differently and this difference can be picked up by a light sensor. Differences can then be changed into an electrical signal..
29 of 49
Give four uses of Infared radiation
be used in cooking (to heat food), security alarms, Remote controls and a substitute for Visible Light to carry information through optical fibres.
30 of 49
Explain how infared radiation can be used to control electrical equipment? (TV Remote to TV)
Remote controls emit pulses of IR to control electrical devices. These pulses act as digital signals, the device will then detect and decode the pulses coming from the remote control and follow the coded instructions
31 of 49
Explain how short wave radio signals can be recieved at long distances?
They are reflected from the earths electrically charged atmosphere
32 of 49
Briefly explain why to recieve FM or TV signals there must be nothing between the aerial and transmitter?
Becuase the signal cannot diffract around hills or travel far through buildings hence why there must be nothing between the aerial and transmitter
33 of 49
Explain why longer wavelength radio waves can travel long distances between the transmitter and reciever?
Longer wavelengths can encounter alot of diffraction because they are large in comparison to the gap or obstacle. Meaning they can bend around hills/buildings
34 of 49
Explain why short wave and medium wave signals are refracted the most in the ionsphere?
Because they are reflected back to the Earth meaning that they can be recieved a long way down from the transmitter
35 of 49
What does the amount a wave is refracted in the ionsphere depend on?
Angle of elevation and frequency
36 of 49
Give two advantages and disadvantages of using DAB?
Disadvantages of using DAB is that sound quality is not as good as FM and since there is limited DAB transmitters some areas don't recive the signals. Advantages less interference and more stations
37 of 49
Name the two types of waves produced by seismic waves
S-waves and P-waves
38 of 49
Briefly describe the the way how a longtidunal wave vibrations move?
vibrations are along the direction that the wave travels
39 of 49
Briefly describe the way how a transversel wave vibrations move?
vibrations are 90 degrees to the direction the wave travels
40 of 49
What state can P-waves travel through? And are they faster than S-waves?
solids and liquids and yes
41 of 49
What state can S-waves move through?
Solids
42 of 49
Give reasons as to why the thining of the ozone is a danger?
Ozone reduces the amount of UV radiation that reaches the earth, since the ozone is being depleted it allows more UV radiation to reach the earth which can be dangerous to our health - it can cause cancer
43 of 49
List some of the dangers of UV radiation?
It can lead to cancers such as skin cancer and eye problems such as cataracts and premature skin againg
44 of 49
Explain how having darker skin can reduce the amount of radiation you can recieve?
It absorbs UV radiation and this prevents some of the damaging radiation from reaching vulnerable tissues in the body
45 of 49
Define an Analogue Signal?
signal which can take any value within a certain range
46 of 49
Define a Digital Signal?
Signal which only can take two values
47 of 49
What are some of the advantages Digital signals have over Analogue signals?
High Quality and multiplexing
48 of 49
Describe the pathway taken by a microwave to a satellite dish?
A Signal from the device (E.g. Phone) is transmitted into Space, where its picked up by a satellite reciever dish. Satellite dish then transmits a signal back to Earth where its recieved by a Satellite dish on the ground
49 of 49

## Other cards in this set

### Card 2

#### Front

What is Specific heat capacity?

#### Back

How much energy a substance can store or how much energy is needed to raise 1kg of a substance by 1 degrees celsuis

### Card 3

#### Front

What is Specific latent heat?

### Card 4

#### Front

What is the formula for Specific heat capacity?

### Card 5

#### Front

What is a formula for Specific latent heat?