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SingaporeCombined ScienceQuick questions
Physics: Waves, Electricity and Magnetism
Quick questions on Magnetism and electromagnetism explained: O-Level Combined Science
5short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What is the magnetic effect of a current?Show answer
When current flows through a wire it produces a magnetic field around the wire, in circles. Winding the wire into a coil (a solenoid) concentrates the field and produces a field like a bar magnet, with a north and a south end.
What are electromagnets?Show answer
An electromagnet is a solenoid with a soft iron core. It is magnetic only while current flows, so it can be switched on and off. It is made stronger by increasing the current, adding more turns to the coil, or using a soft iron core. Soft iron is used because it loses its magnetism when the current stops.
What is q1?Show answer
State two ways to increase the strength of an electromagnet. [2 marks]
What is q2?Show answer
State what is meant by the motor effect. [2 marks]
What is q3?Show answer
Explain why no current is induced when a magnet is held still inside a coil. [2 marks]
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