Electricity - June 2023 Paper 1 Flashcards
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`CHATGPT, JUNE 2023
Explain why the reading on the thermometer stabilizes and becomes equal to the temperature of the iron block when placed in contact with it. [3]
The thermometer and the iron block exchange heat until they reach the same temperature.
(1 mark). Once they are at the same temperature, there is no further net heat transfer between them (1 mark).
This stable point is called thermal equilibrium, where the thermometer’s reading matches the temperature of the iron block (1 mark).
June 2023
The power output of the lamp is 1.0 W when the potential difference across the lamp
is 5.0 V.
A student predicts that the power output would be 4.0 W if the potential difference
was doubled.
Explain why the student is not correct. [2]
the
current and the p.d. would both
need to double[1]
(but the current doesn’t double)
because the resistance of the
filament lamp increases[1]
JUNE 2023
A negatively charged rod is on a balance.
A student puts another charged rod being held stationary above the rod on the
balance.
The rods do not touch each other
Explain why the reading on the balance increases.[3]
there is an additional
(downwards) force on the
balance (increasing the mass
reading)[1]
(because) the (held) rod is
negatively charged[1]
(and rods with) like charges
repel[1]
June 2022
A negatively charged rod is held near an earthed conductor.
Explain why a spark jumps between the negatively charged rod and the earthed
conductor. [3]
the (large) potential difference
between the two objects[1]
(causes negative) electrons /
charges to move (through the
air)[1]
(from the rod) to the conductor[1]
june 2022
Explain why transformer X is used in the National Grid.[4]
transformer X increases
potential difference[1]
and decreases current[1]
reducing (thermal) energy
transfer to surroundings
increasing the efficiency (of
power transmission[1]
June 2022
Explain why transformer Y is used in the National Grid[2]
To decrease a potential difference[1]
to a safer value [1]
What is the equation that links energy transferred, voltage and charge of flow?
E= VxQ
A student investigated how the current in a filament lamp varies with the potential
difference across the filament lamp.
Describe a method the student could use to obtain these results.
You should include a circuit diagram.
[6]
- ammeter in series with filament lamp
- current measured with an ammeter
- voltmeter in parallel with filament lamp
- p.d. measured with a voltmeter
- variable resistor (or variable power pack or variable number of
cells) used to vary current in and p.d. across filament lamp - range of p.d. of 0 to 6 V
- interval of p.d. of 1 V
- reverse connections to power supply to obtain negative values
- take repeat readings and calculate a mean
- discard anomalie
Leannes’s lesson
What happens if a charged and uncharged object meets?
They would attract each other.
Leannes’s lesson
Current is the charge of the flow.
Potential difference is the energy transferred per unit charge.
As the potential differnce increases the electrons gain more energy and vibarte more which increases the temperature and resistance.
LEANNE’S LESSON
The air inside the fridge forms a convcetion current when the fridge door is closed.
Explain why. [4]
Convection in the air is the cycle where hot air rises and cold air sinks. This is because cold air is more dense taht hot air so it sinks, due to particles being close together.
June 2022
There is negatively charged rod on a balance.
Also, there is another charged rod being held stationary above the rod on the
balance.
The rods do not touch each other.
Explain why the reading on the balance increases.[3]
there is an additional
(downwards) force on the
balance (increasing the mass
reading)[1]
(because) the (held) rod is
negatively charged[1]
(and rods with) like charges
repel[1]
June 2022 past paper question
What happens to the power output if the switches in a parallel circuits switches of? [3]
The total resistance of the circuit decreases[1]
so the current increases[1]
which increases the power output[1]
November 2021
It is dangerous for a person to fly a kite near an overhead power cable.
The person could receive a fatal electric shock if the kite was very close to, but not
touching the power cable.
Explain why.[3]
electric field strength is very
high[1]
causing the air to become
ionised[1]
(the kite / string) conducts
charge to the person / earth[1]
Explanation:
The electricity around the power cable is so strong that it can actually change the air nearby.
Making it easier for electricity to move through it this is called ionizing the air which is making the path for electricity to jump.
When the kite gets close, the electricity can use this path to jump from the cable to the kite string.
Since the string is connected to the person, the electricity travels down to them or even into the ground, which can cause a dangerous shock.
November 2021
A cross-section is shown through a power cable.
A 1 metre length of a single aluminium wire is a better conductor than a 1 metre
length of the steel wire.
The individual wires behave as if they are resistors connected in parallel.
Explain why the current in the steel wire is different to the current in a single
aluminium wire.
The potential difference across the wire is the same.[1]
Why is it the same?
This ensures that the power being sent from the power plant stays constant and reliable across the whole line.
(but) the resistance of the steel
wire is greater (and so less
current in the steel)[1]
