Corrections Flashcards

1
Q

When investigating affects of light on an LDR with a lamp where must the experiment be conducted and why

A
  • in a darkened room
  • so no ambient light affects the LDR
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2
Q

How can you measure the volume of an irregular shape lighter than water (3)

A
  • submerge it with a sinker
  • measure the total volume displaced by object and submerging object
  • subtract the volume displaced by sinker alone
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3
Q

explain in terms of particles why solids have greater densities than water

A
  • more closely packed particles
  • more mass per unit volume
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4
Q

voltage of sockets in a ring main

A

230 V

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5
Q

advantages of a ring main (5)

A
  • cables can be made thinner
  • each part of the cable carries less current
  • sockets can be placed anywhere
  • each socket has 230V applied
  • sockets can be operated separately
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6
Q

In the change of state from solid to liquid what does breaking of bonds allow particles to do

A

slide past one another

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7
Q

In the change of state from liquid to gas what does the breaking of bonds allow particle to do

A

allows them to escape from one another

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8
Q

purpose of the iron core in a transformer (2)

A
  • links the alternating magnetic field from the primary to secondary coil
  • strengthens the magnetic field
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9
Q

what type of line of best fit is drawn on a current - voltage graph for a resistor

A

straight line

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10
Q

Describe a test to test if a component is a diode (3)

A
  • connect in series one way and see if the current is high
  • reverse the cell
  • see if the current is zero (a diode only lets current flow one way)
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11
Q

Why does a satellite in geostationary orbit above the equator appear to stay in a fixed place above the Earth (2)

A
  • satellite orbits in the same time
  • that it takes the Earth to spin once
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12
Q

what is the Earth wire

A

takes current away from an appliance when a fault occurs for protection

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13
Q

explain in terms of particles how heat conducts through copper (4)

A
  • the particles vibrate faster
  • they collide with neighbours, transferring heat energy
  • copper also has free electrons that move faster
  • electrons pass on the energy as they move through the lattice
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14
Q

explain why the liquid in the heated solar panel circulates (4)

A
  • heated liquid is less dense
  • heated liquid rises
  • colder liquid falls
  • convection current form
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15
Q

how does a generator make electricity in a power plant (3)

A
  • fuel is burned to heat water
  • kinetic energy of steam turns a turbine
  • turbine turns generator producing electricity
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16
Q

how would you work out if power is proportional to screen size in TV’s

A
  • compare ratio of screen size to power of the 2 TV’s
  • ( TV 1’s screen size divided by power = … and
  • TV 2’s screen size divided by power = …)
  • if the two numbers are the same then the ratio is the same so its true
17
Q

why should consumers be encouraged to choose appliances that use less energy (2)

A
  • so less fossil fuels are burnt
  • reducing impact on global warming
18
Q

what do you use to measure mass

A

a balance

19
Q

how can you measure the volume of an irregular object (3)

A
  • fill a measuring cylinder with water (ensuring there is space left for the pebble). Record the volume in cm3
  • carefully place the pebble into the measuring cylinder and determine the new volume
  • subtract the volume of water from the volume of the water +the pebble
20
Q

what is a transverse wave

A

the vibrations are perpendicular to the direction of wave travel

21
Q

what is a longitudinal wave

A

the vibrations are parallel to the direction of wave travel

22
Q

Describe the function of the Earth wire (2)

A
  • carries current safely to the ground to prevent electrocution
  • if the metal of an appliance frame becomes live
23
Q

state two differences between ac and dc current

A
  • ac is a current that continuously changes direction
  • ac is a current that continuously changes in magnitude
24
Q

why does water move in convection currents when heated (2)

A

-heated water’s volume increases and its density decreases
-cooling water’s volume decreases audits density increases

25
Q

in detail explain the process of conduction in COPPER in terms of motion of particles (6 marker)

A
  • the molecules at the ‘high temperature end’ of the substance gain energy
  • and vibrate with increasing kinetic energy
  • they transfer their energy to neighbouring molecules by collisions and this continues through the body of the material
  • copper has free electrons which gain energy at the ‘high temperature end’
  • and move towards the ‘lower temperature end’
  • transferring energy more quickly
26
Q

Reasons why the use of nuclear power stations have not changed over years (3)

A
  • they do not produce CO2 emissions
  • nuclear power stations run all the time
  • no new nuclear stations have come on line
27
Q

Percentage decrease =

A

Decrease/original amount x 100

28
Q

Comment on the progress being made in achieving the government’s overall target for CO2 emissions by 2027 (2)

A
  • Good progress is being made in the electricity generation sector
  • however there are other sources of emission that haven’t been taken into consideration
29
Q

what word describes the metal casing of an alliance that is in contact with the live wire

A

live

30
Q

explain why an aluminium window loses heat at a faster rate than uPVC window (aluminium has a metal spacer, uPVC - a nonmetal spacer) (4)

A
  • aluminium is a better conductor
  • metal spacer conducts heat from the inner pane to the outer pane
  • increased vibrations pass on energy from one particle to another
  • free electrons transfer energy from a high to low temperature
31
Q

explain how heat is lost through the roof of a house (3)

A
  • heat conducts through the ceiling to the loft
  • as air is heated it becomes less dense and rises
  • creating a convection Curren† in the loft space
32
Q

why does reducing energy loss from homes benefit the environment (3)

A
  • heating is used to replace energy lost
  • if you lose less heat your heating doesn’t need to be on for as long
  • less fossil fuels are burned
33
Q

FULLY describe the National Grid

A

A network of power stations, transformers and power lines all joined together, supplying electricity to consumers. They monitor and respond to changes in supply and demand.

34
Q
A