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Flashcards in P1 Deck (57)
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0
Q

What is happening if an objects temperature rises?

A
  • The object is taking in heat energy
1
Q

How is heat energy measured?

A
  • Joules (J)
4
Q

What is happening if an objects temperature drops?

A
  • the object is giving out heat energy
5
Q

What 3 things does the energy needed to raise the temperature of an object depend on?

A
  • the objects mass
  • the change in temperature required
  • the objects material
6
Q

How do you calculate the amount of energy supplied?

A

Total energy supplied=

Energy supplied per second ✖️ number of seconds

7
Q

What is Specific heat capacity?

A
  • the value of how much energy an object can hold

- the energy needed to raise the temperature of 1kg of material by 1 degree

8
Q

How do you calculate the amount of energy needed to raise the temperature of an object?

A

Energy =

Mass(kg) ✖️ SHC(j/kg) ✖️ temperature change

9
Q

How to you calculate specific heat capacity?

A

Specific heat capacity =

Energy ➗ (mass ✖️ temperature)

10
Q

During the melting and boiling of water, what is the energy supplied used to do?

A
  • to break intermolecular bonds as the water molecules change state.
11
Q

What is Specific Latent Heat?

A
  • the amount of heat energy required to melt or boil 1kg of a material
12
Q

What doses specific latent heat depend on?

A
  • the material

- the state

13
Q

How do you calculate the energy required to boil or melt a certain mass of a material?

A

Energy = mass(kg) ✖️ specific latent heat

14
Q

How do you calculate the payback time of an insulator?

A

Pay back time (years) =

Cost of product ➗ annual saving

15
Q

What is a cavity wall?

A
  • made up of an inner and outer wall with a cavity (space) full of air between them
16
Q

How can heat loss be reduced from a cavity wall?

A
  • by filling the space with air
17
Q

What is energy efficiency?

A
  • A measurement of how good an appliance is at converting input energy into a useful output energy
18
Q

How can energy efficiency be calculated?

A

Efficiency=

(Useful out put energy ➗ total input energy) ✖️ 100

19
Q

What are the 3 ways that heat energy can be trNsferred?

A
  • conduction
  • convection
  • radiation
20
Q

What is conduction?

A
  • the transfer of heat energy through a substance from a hotter region to a cooler region without any movement of the substance itself
21
Q

Why are metals very good conductors?

A
  • because they have free electrons which can move through the material carrying energy
22
Q

What is convection?

A
  • the transfer of heat energy from hotter regions to cooler regions by the movement of particles
23
Q

What type of wave is light?

A
  • transverse wave
24
Q

What are the 3 features of a transverse wave?

A
  • Amplitude:
    > the maximum disturbances caused by the wave
  • Wavelength:
    > the distance between each wave
  • Frequency:
    > the number of waves produced per second
25
Q

What is the Electromagnetic spectrum?

A
  • A continuos spectrum that extends beyond each end of the visible spectrum of light
26
Q

What is the sequence of the Electromagnetic spectrum?

A

Radio waves ➡️ Microwaves ➡️ Infrared rays ➡️

Visible light ➡️ Ultraviolet rays ➡️ X-rays ➡️

Gamma rays

27
Q

How can you calculate the speed of a wave?

A

Wave speed=

Frequency ✖️ wavelength

28
Q

What speed do all electromagnetic waves travel at in a vacuum

A
  • the same speed
29
Q

What is diffraction?

A
  • when the edges of a wave spread out as it passes through a gap or an opening
30
Q

What is maximum diffraction?

A
  • when the gap is the same width as the wavelength of the wave passing through it
  • causes quality of image to reduce
31
Q

When can light and infrared rays be reflected or refracted?

A
  • when they cross a glass-air boundary
32
Q

What does reflection and refraction depend on?

A
  • the Angle of incidence

> if the angle is below the critical angle, the light or infrared is refracted away from the normal

> if the angle is above the critical angle the ray in totally internally reflected and not refracted

33
Q

What are optical fibres and what are they used for?

A
  • Long, flexible, transparent cables of a very small diameter
  • used to send information in the form of pulses of light, or infrared radiation
  • pulses aren’t refracted, they are totally internally reflected
34
Q

What is Electromagnetic radiation ?

A
  • wireless technology

- used to send information without optical fibres

35
Q

What is light used for communication produced by?

A
  • a laser
36
Q

What are the advantages and disadvantages of using Light to send information?

A
  • advantages:
    > travels very fast
    > small loss of signal

Dissadvantages:
> can’t be wireless

37
Q

What are the advantages and disadvantages of using Electrical to send information?

A

Advantages:
> can be sent along wires

Disadvantages:
> signal deteriorates

38
Q

What are the advantages and disadvantages of using Radio waves to send information?

A

Advantages:
> can be wireless

Disadvantages:
> diffraction leads to signal loss

39
Q

What are some uses of lasers?

A
  • surgery
  • dental treatment
  • cutting materials
  • weapon guidance
  • laser light shows
40
Q

What are the waves like in laser light?

A
  • all:
    > have the same frequency
    > are in phase with eachother
    > have low divergence
41
Q

What does ‘in phase mean’?

A
  • all the peaks and troughs match up

> waves in phase transfer a lot of energy

42
Q

What does the amount of radiation that is absorbed or emitted from a surface depend on?

A
  • surface temperature
  • colour- black is good, white and silver are poor
  • texture - dull is good, shiny is poor
43
Q

What are the abilities of microwaves?

A
  • are absorbed by water and fat molecules which causes them to heat up
  • can penetrate about 1 cm of food
  • can cause burns when absorbed by body tissue
  • can travel through glass and plastics
  • are reflected by shiny metal surfaces
44
Q

What are the abilities of Infrared rays?

A
  • used to heat the surface of food in cooking
  • reflected of shiny surfaces
  • absorbed by black objects
45
Q

What can cause microwave signals to be lost or affected?

A
  • large objects blocking the signal
  • poor weather
  • the curvature of the Earth
  • interference between signals
46
Q

What are infrared rays used in? (5)

A
  • remote controls
  • sensors for doors
  • short distance wireless data links for computers or phones
  • burglar alarms ( detecting body heat)
  • security lights
47
Q

What are Analogue signals?

A
  • used to transmit signals
  • vary continuously in amplitude
  • can have any value within a fixed range
48
Q

What are digital signals?

A
  • used to transmit data as a series of pulses.

- do not vary, they have two states, on (1) and off (0)

49
Q

What us multiplexing?

A
  • when two or more digital signals are sent down the same optical fibre at the same time.
  • enables more information to be sent in one go.
50
Q

What are the advantages and disadvantages of wireless communication?

A

Advantages:
> no connections to a phone land-line needed
> portable, convenient! allows access anywhere

Dissadvantages:
> aerial is needed to pick up signal

51
Q

How are satellites used for global communication?

A
  • a signal is sent from a ground station transmitter dish, to a satellite receiver dish.
  • a return signal is then sent by the satellite transmitter to a ground receiver dish.
52
Q

What is the Ionsphere?

A
  • an electrically charged layer in the Earths upper atmosphere
  • reflects longer wavelength radio waves
53
Q

What does Refraction at the interfaces of different layers of the Earths atmosphere result in?

A
  • Waves changing direction

- Diffraction at the edge of transmission dishes causes the waves to spread out, which results in signal loss

54
Q

What are the advantages and disadvantages of DAB radio?

A

Advantages:

  • more stations available
  • less interference with other stations

Dissadvantages:

  • audio quality is not as good as FM broadcasts
  • not available everywhere
55
Q

What are seismic waves?

A
  • shock waves produced by earthquakes
56
Q

What are the two types of Seismic waves?

A

P-waves (primary waves)
- longitudinal and travel through both solids and liquids

S-waves (secondary waves)
- are transverse waves and travel through solids but not liquids. Travel slower than P-waves

57
Q

What will happen to a wave as it passes from one medium to another?

A
  • it will speed up or slow down
58
Q

What is Refraction?

A

-When a wave changes direction when it passes from one medium to another