Phy1 - Energy Flashcards

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1
Q

What is a system?

A

A group of objects

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2
Q

What are the 4 ways energy can be transferred?

A

1) Mechanically (a force moving
2) Heating
3) Electrically (charge being transferred)
4) Radiation

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3
Q

What is “work done” the same as?

A

Energy transferred

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4
Q

What is the unit for work done?

A

Joules (J)

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5
Q

What is the equation for kinetic energy?

A

Ek = ½ × m × v²
Kinetic energy = 0.5 × mass × velocity²

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6
Q

What are the 8 energy stores?

A
  1. Thermal
  2. Kinetic
  3. Gravitational Potential
  4. Elastic Potential
  5. Chemical
  6. Magnetic
  7. Electrostatic
  8. Nuclear
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7
Q

What is a closed system?

A

A system where matter or energy cannot enter or leave

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8
Q

Describe the energy changes in a falling ball

A

The ball’s gravitational potential energy would decrease as it came closer to the ground.
The ball’s kinetic energy would increase as it speeds up

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9
Q

What is specific heat capacity?

A

The amount of energy needed to increase 1kg of a substance by 1⁰C

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10
Q

What is the equation for power?

A

P = E ÷ T
Power = Energy transferred ÷ time
or
P = WD ÷ T
Power = Work Done ÷ time

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11
Q

Name the energy store in a streched or compressed spring

A

Elastic potential energy

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12
Q

What does “conservation of energy” mean?

A

Energy can be stored, transferred or dissipated. It can never be created or destroyed

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13
Q

Describe the energy transfer involved in a person lifting a weight

A

• The person’s chemical energy
store decreases
• The kinetic energy store of the
person’s arm and the weight
increases.
• The gravitational potential
energy store of the person’s
arm and the weight increases

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14
Q

A book on the top shelf has a
gravitational potential energy
store of 100 J. The book falls. How
much energy will be in the book’s
kinetic energy store as it hits the
ground?

A

100 J

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15
Q

What is another name for “wasted energy?”

A

Dissipated energy

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16
Q

What are lubricants used for?

A

To reduce friction between moving objects

17
Q

List some examples of house insulation

A

• Cavity wall insulation (reduces
convection)
• Loft insulation (reduces
convection)
• Double-glazed windows
(reduces conduction)
• Draught excluders (reduces
convection)

18
Q

Describe how energy is transferred by convection

A

• Particles gain energy
• Particles move further apart
• The fluid becomes less dense
• Particles rise and transfer
energy to other particles
• The fluid becomes more dense
Particles fall
• A convection current is formed

19
Q

What is the equation for efficiency?
(power output)

A

Efficiency = Useful power output ÷ Total power output

20
Q

Why are homes insulated?

A

To reduce heat loss

21
Q

Describe how energy is transferred using conduction

A

• Particles vibrate more
• Particles bump into eachother
• This exchanges energy

22
Q

To insulate a house, would you want the insulation to have a high or low thermal conductivity?

A

Low (to reduce heat loss)

23
Q

What is the equation for energy transferred?
(energy output)

A

Energy transferred = Useful output energy transferred ÷ Total input energy transferred

24
Q

List 7 renewable energy stores

A

• Bio-fuel
• Wind
• Hydro-electricity
• Geothermal
• Tidal
• Solar
• Water waves

25
Q

List 4 non-renewable energy sources

A

• Coal
• Oil
• Nuclear
• Gas

26
Q

What do you call energy stores that do not run out?

A

Renewable

27
Q

Name 2 gases that can be releases when burning fossil fuels and the problems they cause to the environment

A

Carbon dioxide - Global warming
Sulfur dioxide - Acid rain

28
Q

What are the 3 types of fossil fuels?

A

• Coal
• Oil
• Gas

29
Q

Which 3 energy stores are not reliable?

A

• Wind
• Waves
• Solar

30
Q

Describe how solar cells work and give some advantages and disadvantages

A

Solar cells absorb light energy and
transfer it into electrical energy.
(+) Do not produce CO2
(+) Expensive to buy and install
(+) Useful in remote places -can
be used on a small scale to power
road signs.
(-) Not reliable - only work when
sunny
(-) They do not produce electricity
at night

31
Q

Describe how electricity is produced using hydroelectric power and give some advantages and disadvantages

A

• Water collected in a large dam/
reservoir
• Water falls from a height and
falls through turbines
• The turbines drive a generator
that generates electricity
(+) Doesn’t produce CO2 or other
pollutants. Can immediately
generate electricity to meet
sudden surges in demand for
electricity
(-) High initial costs, damage to the environment, habitat loss, visual pollution,

32
Q

Describe how electricity is produced using tidal power and give some advantages and disadvantages

A

• A tidal barrage is built across
an estuary.
• The tides are produced by the
gravitational pull of the Sun
and Moon.
• As the tide comes in/out, it
builds up behind the barrage
and is then released through
the barrage at a controlled
speed.
• As the water moves through,
it turns turbines that turn
a generator to produce
electricity

(+) reliable - two tides every day,
doesn’t produce CO2 or other
pollutants.
(-) high installation costs, damage
to wildlife, visual pollution
prevents access to boats

33
Q

Give 3 disadvantages of nuclear power

A

• Lots of nuclear waste is produced
• Risk of major catastrophe
• High cost of building the plant

34
Q

Describe how energy is produced using geothermal power and give some advantages and disadvantages

A

• Water is heated by naturally
hot rocks underground.
• Water is turned into steam.
• The steam turns a turbine that
drives a generator to generate
electricity
(+) Reliable, doesn’t produce CO2
or other pollutants
(-) Not many suitable locations
where hot rocks are close to the
surface
(-) High cost of building the power
plant

35
Q

Describe how energy is produced using wave power and give some advantages and disadvantages

A

Waves turn turbines that turn a
generator to produce electricity
(or the wave movement
compresses air and the air turns
the turbine).
(+) Doesn’t produce COz or other
pollutants
(-) Spoils view, disturbs seabed
and marine habitats

36
Q

Describe how energy is produced using biofuels and give some advantages and disadvantages

A

Plants and animal manure are
used as a fuel. They are used in a
power station to heat water. The
water turns to steam which turns
a turbine that drives a generator
and produces electricity.
(+) carbon neutral (no net increase
of CO2) in atmosphere. Reliable
because crops don’t take long to
Srow
(-) biodiversity loss in fields
used to grow crops for biofuels
Deforestation to grow crops.

37
Q

List 6 energy sources that are reliable

A

• Biofuels
• Fossil Fuels (coal, oil, gas)
• Nuclear
• Geothermal
• Tidal
• Hydroelectric

38
Q

Describe how you would measure the specific heat capacity of a block of metal (required practical)

A

• Measure the mass of the metal
• Put a thermometer into the
hole in the block and measure
the starting temperature of the
block.
• Connect an immersion heater
to a joulemeter and a power
pack and place the heater into
the metal block
• Insulate the block.
• Heat the block for 5 minutes
• Calculate the temperature
change of the block.
• Read the joulemeter
to calculate the energy
transferred to the block.
• Calculate specific heat
capacity (c) using the following
equation: c= E/(m0)