Electromagnets and Applications
Physics ⇒ Electricity and Magnetism
Electromagnets and Applications starts at 8 and continues till grade 12.
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See sample questions for grade 11
A relay is used to control a high voltage circuit with a low voltage signal. Which part of the relay is responsible for this function?
A solenoid has 500 turns and carries a current of 2 A. If the number of turns is doubled while keeping the current constant, by what factor does the magnetic field inside the solenoid change?
A solenoid is 0.5 m long and has 1000 turns. If a current of 3 A flows through it, calculate the magnetic field inside the solenoid. (Use μ₀ = 4π × 10⁻⁷ T·m/A)
A student wraps a wire around a nail and connects it to a battery, creating an electromagnet. If the student increases the voltage of the battery, what happens to the strength of the electromagnet?
Describe how an electric bell works using the principle of electromagnetism.
Describe the role of electromagnets in a loudspeaker.
Explain why electromagnets are used in scrapyard cranes instead of permanent magnets.
Explain why soft iron is preferred over steel as the core material in electromagnets.
Explain why the core of an electromagnet should not be made of a permanent magnet.
If the current in the coil of an electromagnet is doubled, what happens to the magnetic field strength?
If the current through an electromagnet is reversed, what happens to its north and south poles?
In a relay, what is the function of the electromagnet?
State one advantage and one disadvantage of using electromagnets over permanent magnets.
State one practical application of electromagnets in daily life.
State the right-hand grip rule for determining the direction of the magnetic field around a current-carrying solenoid.
