P1 energy for the home IN PROGRESS Flashcards
Temperature is a measure of what?
Hotness
What happens to a substance when it is heated
It gains kinetic energy (KE)
If there is a difference in heat what will happen?
The energy will flow between them
The greAter the heat difference equals what..
Faster rate of cooling or heating.
What does specific heat mean
It tells you how much energy stuff can hold
What is waters specific heat capacity ?
4200 j/kg/Celsius
Energy=
Mass x specific heat capacity x temp change
How do you break intermolecular bonds?
Use heat
When a substance is condensing or freezing what happens?
Bonds are formed and energy is released
What is specific latent heat
It’s the energy needed to change heat
Other formulae for energy
Mass x specific latent heat
Where does conduction occur
Mostly in solids
Define conduction of heat
It is the process where vibrating particles pass on Extra kinetic energy to neighbouring particles
Why do metals conducts heat well.
Because some of their electrons are free to move inside the metal
Where does convection occur
In liquids and gasses
Define convection
More energetic particles move from hot to cold and take heat energy with them
Radiators in homes what do they do?
Use convection to heat rooms
What is radiation?
Heat from the sun
Name the three ways heat can be transferred
Conduction
Convection
Radiation
What makes radiation different
It does not need a material to travel in fin works in a vacuum
It only happens in transparent things such as air, glass and water
What emits radiation?
All objects
Are Matt black surfaces good or bad absorber and emitters?
Good
Light coloured smooth and shiny objects are goor or bad are emitting and absorbing?
Bad they reflect but don’t absorb or emit
What is heat radiation good for?
Cooking
What kitchen appliances use radiation
Grills and toasters and microwaves
How can you save money and energy in your home
Insulation
What is a source?
Something that emits energy or heat such as a radiator
Name 6 ways to insulate your house
Loft insulation Cavity wall insulation Draught proofing Thick curtains Double glazing Hot water tank
What’s a thermogram
It shows heat and specifically where your house is leaking or losing heat
If a house looks hot ( white yellow and red) what does it mean?
It means the house is losing heat form that area
The total energy output is the same as …
The energy input
Why is only some of the output energy useful
Some of the input energy is lost or wasted as heat
The less energy wasted equals what..
Higher efficiently
Efficiency formulae …
Useful energy output
————————– (X100%)
Total energy input
What is a sankey diagram
It shows energy transformations. It shows how much of the input energy is useful at the end and how much is being wasted
What do waves have (3 things)
Amplitude
Wavelength
Frequency
What does amplitude mean
Is the height form the rest point of the wave till the crest at the top
What is the wavelength meaning.
It is the length of a full wave from crest to crest
What is wave frequency
It is the number of complete cycles or oscillations passing a certain point per second
Formulae for wave speed…
Frequency x wavelength
One kilohertz =
1000 hertz Hz
1megahertz =
1000000 hertz
All waves can be what…
Reflected refracted and diffracted
What does light reflection do?
It allows us to see objects as the light bounces off them into our eyes
What is the law of reflection?
Angle of incidence = the angle of reflection
What does the total internal reflection depend on?
The critical angle
What happens if the angle of incidence is less than the critical angle…
Most of the light is refracted into the outer layer but some is internally reflected
What happens if the incidence angle is equal to the critical angle….
The ray goes along the surface with lots of internal reflection
What happens if the incidence angle is bigger than the critical angle….
No light comes out as it is all internally reflected so total internal reflection
What does diffraction mean
Waves spreading out
The amount of diffraction in a wave depends on what…
The size of the gap relative to the wavelength.
Name the 7 types in em wave s
Grumpy. Gamma rays X men. X rays Urinate Ultra violet Violently. Visible light In infa red My micro waves Room radio waves
How can we communicate with light
Morse code
What do lasers produce?
Intense beams of monochromic light
It has a low divergence compared to torches and it has a narrow beam
What uses lasers to read digital information
CD players