Frage 1
Frage
Which way do magnetic field lines point?
Antworten
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North pole to south pole
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South pole to north pole
Frage 2
Frage
True or false? An electromagnet is a piece of insulated wire wrapped around an iron core which can be temporarily magnetised if current flows through it.
Frage 3
Frage
Which of these devices make use of electromagnets?
Antworten
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Scrapyard crane
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Hydraulic jack
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Circuit breaker
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Fuse
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Electric bell
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Filament bulb
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Relay
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Lever
Frage 4
Frage
What does the first finger stand for in Fleming's left-hand rule of the motor effect?
Antworten
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Direction of force
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Direction of field lines
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Direction of current
Frage 5
Frage
True or false? The device used to make a motor spin without tangling its wires is called a switch-mode commutator.
Frage 6
Frage
True or false? A loudspeaker produces sound when a coil is repeatedly moved back and forth by the motor effect.
Frage 7
Frage
Which scientist discovered electromagnetic induction?
Antworten
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Andre-Marie Ampere
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Alessandro Volta
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Georg Ohm
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Michael Faraday
Frage 8
Frage
How can we reverse the direction of the force in the motor effect?
Antworten
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Reverse the magnetic field lines
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Reverse the direction of the current
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Reverse the direction of the current and the magnetic field lines
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Use alternating current instead of direct current
Frage 9
Frage
True or false? A potential difference is induced across a wire when it is moved to cut across magnetic field lines.
Frage 10
Frage
True or false? An induced potential difference will never lead to an induced current.
Frage 11
Frage
How many coils of wire does a transformer have?
Frage 12
Frage
Which transformer has fewer turns on the secondary coil than on the primary coil?
Antworten
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Step-up transformer
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Step-down transformer
Frage 13
Frage
True or false? Transformers only work when a direct current is passed through them.
Frage 14
Frage
What is the core of a switch-mode transformer made of?
Antworten
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Iron
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Steel
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Cobalt
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Nickel
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Ferrite
Frage 15
Frage
True or false? Having a higher voltage in transmission cables reduces I^2R losses and so conserves as much energy as possible.
Frage 16
Frage
What is the potential difference across the primary coil of a transformer if the primary coil has 60 turns, the secondary coil has 20 turns and the potential difference across the secondary coil is 150V?
Frage 17
Frage
What is the current across the secondary coil of a transformer if the current across the primary coil is 4A, the potential difference across the primary coil is 600V and the potential difference across the secondary coil is 800V?
Frage 18
Frage
Which of these is used to record potential difference?
Antworten
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Endoscope
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Blood pressure gauge
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ECG
Frage 19
Frage
True or false? MRI stands for magnetic resonance imaging.
Frage 20
Frage
True or false? MRI is an ionising form of imaging, while CT scanning is not.