Gcse Physics: Circuits
Gcse Physics: Circuits
(a) In the circuit below, lamps P and Q are identical. The reading on the ammeter is 3A. The cell shown is of
emf. 6V.
A
P
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Q
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Calculate the current that passes through lamp P.
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GCSE PHYSICS CIRCUITS
(a) Resistors of 5 ohms and 10 ohms are connected in series with a battery supplying 3 volts.
What is the total resistance ?
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GCSE PHYSICS CIRCUITS
(a) Resistors of 2 ohms and 4 ohms are connected in parallel across a battery supplying 6 volts.
Another resistor of 5 ohms is connected in series with the battery. Draw the circuit.
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GCSE PHYSICS CIRCUITS
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(ii) How many joules of energy are transferred by the lamp in 5 minutes ?
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(b) (i) Calculate the current passing through the lamp when it is connected to a 12 V supply.
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GCSE PHYSICS CIRCUITS
10 Ω
20 Ω
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(a) Calculate the current flowing through the 20 ohm resistor.
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(b) Calculate the current flowing through the battery.
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GCSE PHYSICS CIRCUITS
10 Ω
10 Ω
10 Ω
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6V
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(b) Calculate the total resistance in the circuit.
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GCSE PHYSICS CIRCUITS
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(b)In which arrangement will the current in the circuit be larger? Explain your answer.
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GCSE PHYSICS CIRCUITS
12 Ω 3Ω
S1
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S2
6Ω 6Ω
(a) Calculate the total resistance when both switches are closed.
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(b)Calculate the total current supplied when both switches are closed.
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(c) Calculate the current in the 3 Ω resistor when switch S1 is closed and switch S2 is open.
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(d) Calculate the current supplied when both switches are open.
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GCSE PHYSICS CIRCUITS
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(b)(i) What is meant by an electric current ?
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(ii) State in which of the following circuits the lamp would light. There may be more than one correct
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answer.
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A B C D E
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GCSE PHYSICS CIRCUITS
6V 6V
L1 A1 1.5 A
L2
A2
L3
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V
(a) Indicate on the diagram where you would insert a switch so that it will switch on or off lamps L2
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and L3, but will not affect lamp L1. [1]
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GCSE PHYSICS CIRCUITS
(a) An ammeter of low resistance is used to measure the current flowing in a circuit.
Explain why it must have a low resistance.
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(ii) Should a voltmeter have a high or low resistance ? Explain your answer.
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GCSE PHYSICS CIRCUITS
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(b) Draw a suitable circuit that could be used for the investigation.
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GCSE PHYSICS CIRCUITS
Below are shown graphs of I against V for three different components; a diode, a lamp filament
and a metal wire.
I I I
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V V V
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A B C
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GCSE PHYSICS CIRCUITS
A machine in a workshop will only operate when the safety guard is in place. There is a large switch
on the machine and a switch where it is plugged into the mains.
(a) (i) Draw a circuit diagram showing the switches for the machine.
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(ii) Explain why the switches are placed in the circuit in the way in which you have drawn them.
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(b) Two switches are used when you want to able to operate something from two different places.
(eg a light at each end of a corridor).
Explain how the arrangement of the switches will differ from that in the machine.
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GCSE PHYSICS CIRCUITS
A student is asked to investigate how the resistance of a wire varies with its length.
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GCSE PHYSICS CIRCUITS
(ii) What can you conclude about how resistance of the wire varies with length?
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GCSE PHYSICS CIRCUITS
A B
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C D [4]
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(b) What is the purpose of component D ?
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GCSE PHYSICS CIRCUITS
(a) Write down the voltage shown on the voltmeter in each of the following circuits.
(i) +
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(ii) + +
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(iii) + +
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(b) Explain why you cannot light a car headlamp bulb with a 1.5 V battery.
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(c) What happens to the size of a current in a circuit when the voltage increases?
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GCSE PHYSICS CIRCUITS
Here is a list some materials in order of their ability to conduct electricity. The best conductor is
at the top and poorest one at the bottom.
silver
copper
aluminium
water
PVC
rubber
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(a) Why is silver not used?
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(b) Aluminium is used in overhead power cables.
Why is copper not used?
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(c) Which two materials from the list are used to insulate electrical wires?
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(d) Explain why bathrooms are always fitted with pull-cord switches.
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GCSE PHYSICS CIRCUITS
Christmas tree lights are usually wired in series. If one bulb stops working, the others do too.
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(b) If there are 20 bulbs in a set of Christmas tree lights which operate from the mains (240 volts), what would
be the voltage across each bulb?
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(c) Why is it wrong to replace a bulb from a 20-bulb set of lights with one from a 40-bulb set?
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