Download 1) Starter: Conduction, Convection, Radiation Extension: E – Energy

1) Starter: Conduction, Convection, Radiation
Extension: E – Energy; m – Mass; c – Specific Heat Capacity; θ – Temperature change.
The specific heat capacity of a substance is the amount of energy needed to change the
temperature of 1 kg of the substance by 1°C.
2) Starter: The payback time of an energy-saving solution is a measure of how cost-effective it
is. Here is the equation to calculate payback time:
payback time (years) = cost of installation (£) ÷ savings per year in fuel costs (£)
Extension: LED – large light arrow compared to heat; Filament – large heat compared to
light. Correctly labelled.
3) Starter: unit of energy, 1000W of energy in 1 hour.
Extension: 2,000 J (2 kJ).
4) Starter: any 3 of: coal oil, gas, nuclear, wind, wave, tidal, biomass etc
Extension: gas-fired station (shortest start-up time); oil-fired station; coal-fired station; nuclear
power station (longest start-up time). Base load – Nuclear, Peak times - Gas.
5) Starter: Increase and decrease the voltage to reduce energy loss in the cables
Extension:
Electricity from a power station goes to:
1. step-up transformers
2. high voltage transmission lines
3. step-down transformers
4. consumers, for example homes, factories and shops.
6) Starter: Gamma, X-Ray, UV, visible (V,I,B,G,Y,O,R), IR, Microwaves, Radio waves
Extension:
|||||| | | | | |||||| | | | | ||||||
Compression
Rarefraction
7) Starter: v is the wave speed in metres per second, m/s; f is the frequency in hertz, Hz; λ
(lambda) is the wavelength in metres, m.
6
Extension: 300,000,000/100 = 30,000,000m (3x10 m)
8) Starter: i=r
Extension:
9) Starter: When waves meet a gap in a barrier, they carry on through the gap. However, the
waves spread out to some extent into the area beyond the gap. This is called diffraction.
Extension:

a gap similar to the wavelength causes a lot of spreading with no sharp shadow, eg
sound through a doorway

a gap much larger than the wavelength causes little spreading and a sharp shadow,
eg light through a doorway.
10) Starter: When a source moves towards an observer, the observed wavelength decreases and
the frequency increases.
When a source moves away from an observer, the observed wavelength increases and the
frequency decreases.
Extension: Astronomers have found that the further from us a star is, the more its light is red-shifted.
This tells us that distant galaxies are moving away from us, and that the further away a galaxy is, the
faster it's moving away.
Since we cannot assume that we have a special place in the Universe, this is evidence for a generally
expanding universe. It suggests that everything is moving away from everything else.