Download Unit 1 Physics flashcards

Page 1
What type of radiation
transmits heat energy?
Complete this sentence
Hotter objects emit …………
infrared radiation than cooler
objects.
What type of surfaces are
good absorbers and good
emitters of infrared radiation?
What type of surfaces are
poor absorbers and poor
emitters of infrared radiation?
What type of surfaces are
good reflectors of infrared
radiation?
What can we say about the
arrangement of particles
(and kinetic energy) in
solids?
What can we say about the
arrangement of particles
(and kinetic energy) in
liquids?
What can we say about the
arrangement of particles
(and kinetic energy) in
gases?
Describe how heat energy can
be transferred by conduction.
Why are metals very good
conductors of heat?
Describe how heat energy can
be transferred by convection.
How is heat lost by
evaporation and gained by
condensation?
Page 2
Hotter objects emit more
infrared radiation than cooler
objects.
Heat energy is transmitted by
infra-red radiation.
Light, shiny surfaces are
poor absorbers and poor
emitters of infrared radiation.
Dark, matt surfaces are good
absorbers and good emitters
of infrared radiation.
In solids, the particles are close
together and arranged in a regular
pattern. The particles are not moving
from place to place but they are
vibrating. Particles have a small
amount of kinetic energy.
Light, shiny surfaces are
good reflectors of infrared
radiation.
In gases, the particles are far apart.
The particles are moving very rapidly
from place to place. Particles have a
very large amount of kinetic energy.
In liquids, the particles are close
together and not arranged in any
pattern. The particles are moving from
place to place. Particles have a large
amount of kinetic energy.
Metals are very good
conductors of heat because
they have free electrons
which can move and transfer
the heat energy.
Conduction takes place best in solids
because the particles are close together.
If we heat the solid, the particles gain
kinetic energy and vibrate more. This
vibration is passed onto nearby particles
causing them to vibrate, spreading the
heat energy.
When a liquid turns to a gas (evaporation) the
particles gain kinetic energy. This energy is
transferred from the surface, which cools down.
Convection takes place in liquids and
gases. When they are heated, the
particles move further apart. This
causes the liquid/gas to become less
dense and move up. Cooler regions
sink to take their place. This is a
convection current.
When a gas turns to a liquid (condensation) the
particles lose kinetic energy. This energy is
transferred to the surface, which warms up.
Page 3
Describe the factors that
increase the rate of
evaporation.
Explain why animals in hot
conditions usually have large
ears and animals in cold
conditions usually have small
ears.
What is meant by an
insulator? Describe in terms
of particles how these work.
What does the U-value tell us
about an insulator?
What is meant by the specific
heat capacity of a substance?
Complete this sentence:
Energy can neither be ………..
nor ………….. but it can be
transferred.
When energy is transferred,
some is often wasted. What
happens to wasted energy?
How do we calculate the
efficiency of a device?
State the energy transfers
taking place in a food mixer.
Which energy transfers are
wasted?
How do we calculate the total
amount of energy transferred
by an appliance in a given
time?
How many kilowatt-hours are
used by a heater with a power
of 2kW running for 2 hours.
What is meant by the payback
time for different methods of
home insulation?
Page 4
Heat is lost faster from objects with a large
surface area.
Animals in hot conditions have to lose body heat
so they often have larger ears which increases
their surface area helping to lose heat.
Animals in cold conditions have to retain their
body heat so they often have smaller ears which
reduces their surface area, reducing heat loss.
These conditions make evaporation
faster:
Warmer conditions
•
Dry conditions (not humid)
•
Windy conditions
•
The U-value tells us the
amount of heat energy that
can pass through an
insulator. Good insulators
have a low U-value.
Insulators reduce heat
transfer. They have large
gaps between particles so
vibrations cannot easily pass
between them.
Energy can neither be created
nor destroyed but it can be
transferred.
The specific heat capacity of a
substance tells us the amount
of energy required to change
the temperature of 1kg of the
substance by 1oC.
Efficiency = useful energy out
total energy in
Wasted energy is eventually
transferred to heat, warming
the surroundings. This energy
is spread out and is less
useful.
x 100
The unit of efficiency is %.
Remember that efficiency cannot
be greater than 100%.
E =
P
x
t
E = energy in Joules (or kilowatt-hours)
P = power in Watts (or kilowatts)
t = time in seconds (or hours)
Different methods of home insulation
save different amounts of money in
reducing energy use. The payback
time tells us how long it takes to save
enough money to pay for the cost of
installation.
Electrical energy is
transferred to kinetic energy,
heat energy (wasted) and
sound energy (wasted).
A heater with a power of 2kW
running for 2 hours uses a
total of 4 kilowatt-hours.
Page 5
How do we calculate the
payback time?
Loft insulation costs £200 to
install and saves £100 each
year. Calculate the payback
time.
Complete:
What is meant by geothermal
energy?
In some power stations, water is
heated and turned to ……….. This
drives a ……….. connected to a
……………….. generating electricity.
When can small-scale
electrical production be useful
(eg solar cells).
What is meant by carboncapture and storage?
State the advantages and
disadvantages of generating
electricity by burning fossil
fuels.
State three examples of fossil
fuels?
Which elements are used to
generate electricity in nuclear
power stations?
State the advantages and
disadvantages of generating
electricity by nuclear power.
State the advantages and
disadvantages of generating
electricity by solar power.
State the advantages and
disadvantages of generating
electricity by wind power.
Page 6
Payback time = 2 years.
Payback time = cost of installation
saving per year
Geothermal energy is available
in volcanic areas. Hot water
and steam rise to the surface.
The steam is used to drive
turbines, generating electricity.
In some power stations, water
is heated and turned to
steam. This drives a turbine
connected to a generator
generating electricity.
Carbon dioxide (eg from power
stations) is trapped and stored so
it does not enter the atmosphere.
This can be done in old oil and gas
fields e.g. under the North Sea.
Small-scale electrical
production can be useful when
it is not economical to
connect to the National Grid,
for example roadside signs.
•
•
•
Fossil fuels include:
Coal
Oil
Gas
Advantages
Very reliable, generating lots of electricity
when we need it.
Relatively cheap
•
Disadvantages
• Non-renewable. Fossil fuels are running out.
Produces carbon dioxide which leads to
•
global warming.
•
Advantages
Very reliable, generating lots of electricity
when we need it.
• Does not produce carbon dioxide and does
not contribute to global warming.
Disadvantages
Expensive to build and decommission
•
• Potentially dangerous. If an accident occurs,
radioactive materials could be released.
Nuclear power stations use
uranium or plutonium.
Advantages
• Does not produce carbon dioxide and does
not contribute to global warming.
Renewable. Will not run out.
•
Disadvantages
Unreliable. Will not generate electricity on
•
days when there is little wind.
• Wind turbines contribute to visual pollution.
Advantages
• Does not produce carbon dioxide and does
not contribute to global warming.
Renewable. Will not run out.
•
Disadvantages
Unreliable. Will not generate electricity on
•
very cloudy days or at night.
•
Page 7
What is meant by the startup time
for a power station? Which fossil
fuel power stations have the
shortest startup time?
Why are nuclear power
stations so expensive?
State the advantages and
disadvantages of generating
electricity by hydroelectric
power.
State the advantages and
disadvantages of generating
electricity by wave and tidal
power.
How can we match the supply
of electricity to the demand for
electricity?
How does a pumped-storage
system help us to manage the
changing demand for
electricity?
What are the advantages and
disadvantages of overhead
power lines and underground
power cables?
State the advantages and
disadvantages of generating
electricity by burning
biofuels.
What is meant by the National
Grid?
What does a step-up
transformer do in the National
Grid?
What does a step-down
transformer do in the National
Grid?
Why is electricity transmitted
at extremely high voltages
through power cables from
power stations?
Page 8
Nuclear power stations are
very expensive to build and
decommission (dismantle at
the end of their useful life).
The startup time is the time taken to
produce electricity when a power
station is switched on. Gas-fired
power stations have the shortest
startup time, followed by oil. Coal has
the longest startup time.
Advantages
• Does not produce carbon dioxide and does
not contribute to global warming.
Renewable. Will not run out.
•
Disadvantages
• Only useful in certain countries (for example
the UK).
Tidal power destroys habitats e.g. birds.
•
Advantages
• Does not produce carbon dioxide and does
not contribute to global warming.
Renewable. Will not run out.
•
Disadvantages
• Only useful in certain countries (those with
lots of fast-flowing rivers).
Dams destroy habitats by flooding.
•
In pumped storage, when electricity demand
is low (eg at night), electricity is used to pump
water uphill into a reservoir. This stores
energy as gravitational potential energy.
When demand is higher, the water is allowed
to flow downhill through turbines generating
electricity.
Electricity demand changes during the day
(for example very low at night). Power stations
cannot easily be turned on and off and
electricity cannot easily be stored. We need
large power stations (eg nuclear) to provide
the base-load and then gas-fired power
stations which can be turned on and off as
demand changes.
Biofuels include wood-chippings from
the timber industry and methane gas
from landfills. These are renewable
and relatively cheap. Although carbon
dioxide is released, in some cases
(eg wood), this was taken in by the
growing plants.
Overhead power lines are cheaper to install and
easier to maintain/repair. However, they can be
affected by weather and can be a hazard e.g. to
low-flying aircraft. They also cause visual pollution
(pylons are unattractive).
Underground power cables are expensive to install
and repair. However, they are not affected by
weather and are not hazardous in most cases.
A step-up transformer
increases the voltage of the
electricity supply from the power
station before it is transmitted
through power cables.
The National Grid is a system
of transformers and power
cables.
Increasing the voltage means that
we can transmit electricity at a
lower current. A lower current
reduces the energy lost as heat
as the electricity passes through
the cables.
A step-down transformer
decreases the voltage of the
electricity supply from the
power cables before passing
to peoples’ homes.
Page 9
What do waves transfer?
What type of wave is shown by
this diagram?
Complete this sentence:
In a transverse wave, the
oscillations are ………………
to the direction of energy
transfer.
What type of waves is shown
by this diagram?
Complete this sentence:
In a longitudinal wave, the
oscillations are ………………
to the direction of energy
transfer.
Give an example of
transverse waves.
Give an example of
longitudinal waves.
What can we say about the
speed of electromagnetic
waves in a vacuum?
State the order of the
electromagnetic spectrum.
Which electromagnetic wave
has the highest frequency?
Label the compressions and
rarefactions on this
longitudinal wave.
Label the wavelength and
amplitude on this wave.
Page 10
This shows a transverse
wave.
Waves transfer energy.
This diagram shows a
longitudinal wave.
In a transverse wave, the
oscillations are perpendicular
(right angles) to the direction
of energy transfer.
Transverse waves include
electromagnetic waves (eg
light, infrared).
In a longitudinal wave, the
oscillations are parallel to the
direction of energy transfer.
All electromagnetic waves
travel at the same speed
through a vacuum.
Longitudinal waves include
sound waves.
Gamma rays have the
highest frequency.
Gamma (shortest wavelength, highest energy)
X rays
Ultraviolet
Visible light
Infrared
Microwaves
Radio waves (longest wavelength, lowest
energy)
wavelength
compression
amplitude
wavelength
rarefaction
Page 11
What do we call an imaginary
line that scientists draw at
right angles to a mirror?
What happens when a wave is
refracted?
What happens to a wave when
it slows down (eg light
passing into a glass block).
What happens to a wave when
it speeds up (eg light passing
out of a glass block).
What is the equation for the
speed of a wave?
What is meant by the
frequency of a wave?
What is the unit of
frequency?
How are radio waves used for
communication?
How are microwaves used for
communication?
How are infrared waves used
for communication?
How is visible light used for
communication?
What can we say about the
angle of reflection and the
angle of incidence when a
wave reflects?
Page 12
When a wave is refracted, it
changes direction as it slows
down or speeds up.
The imaginary line drawn at
right angles to a mirror is
called the normal.
When a wave speeds up, it
bends away from the normal.
When a wave slows down, it
bends towards the normal.
The frequency of a wave is the
number of waves per
second. The unit is hertz (Hz).
v
=
f
x
v = speed (m/s)
f = frequency (hertz)
= wavelength (m)
Radio waves are used for radio
and TV signals. Certain radio
waves can diffract around hills
so houses in valleys can receive
radio signals.
The unit of frequency is the
hertz (Hz).
Infrared waves are used by
remote controls.
Microwaves are used by
mobile phones to
communicate with the base
station. They are also used to
send signals to satellites.
Visible light is used for
photography.
angle of
incidence
angle of
reflection
angle of incidence = angle of reflection
Page 13
What can we say about the
image produced in a plane
mirror?
How is a sound wave
transmitted?
What happens to a sound
when the amplitude of the
sound wave is increased?
What happens to a sound
when the frequency of the
sound wave is increased?
What is an echo?
What is meant by diffraction?
What is meant by the Doppler
effect?
What happens to the observed
wavelength and frequency of a
wave if the source is moving
away from the observer?
What happens to the observed
wavelength and frequency of a
wave if the source is moving
towards from the observer?
What is meant by the redshift?
What do we know about the
movement of galaxies that are
further away?
How does red-shift support
the Big Bang theory?
Page 14
Sound waves cause vibration
of the particles in the medium
in which they are travelling (eg
air or water).
The image produced in a
plane mirror is virtual.
When the frequency of a
sound wave is increased, the
sound has a higher pitch.
When the amplitude of a
sound wave is increased the
sound is louder.
When a wave passes through a
gap that is about the same size as
the wavelength, the wave
spreads as it passes through the
gap. This is called diffraction.
An echo is a reflected sound.
The wavelength will increase
and the frequency decrease.
When a wave source is moving
relative to an observer, there is a
change in the observed
wavelength and frequency.
This is the Doppler effect.
The observed wavelength of
light from distant galaxies
appears to be increased. This
tells us that galaxies are
moving away.
The wavelength will decrease
and the frequency increase.
The Big Bang theory says that the
universe began from a very small
initial point and has expanded
out. This is supported by red-shift
which shows that the universe is
expanding.
The more distant a galaxy,
the faster it is moving away.
Page 15
What is CMBR and how does
it support the Big Bang
theory?
Page 16
CMBR (cosmic microwave
background radiation) is
microwave radiation filling the
universe. This comes from the
radiation present shortly after the
Big Bang.
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