Magnetic Effects of Electric Current

Grade 9 Science — Magnetic Effects of Electric Current: 25 practice questions with instant scoring and explanations.

1. A magnetic field is produced by:
2. The direction of magnetic field around a current-carrying wire is given by:
3. When current passes through a solenoid, it acts as:
4. An electromagnet can be made stronger by:
5. Fleming's left-hand rule relates:
6. In Fleming's left-hand rule, the thumb points towards:
7. An electric motor works on the principle of:
8. In a DC motor, the split ring commutator functions to:
9. The coil in an electric motor rotates because:
10. Electromagnetic induction is the phenomenon of:
11. According to Faraday's law, induced EMF is proportional to:
12. Lenz's law states that the induced current:
13. A transformer is based on the principle of:
14. In a step-up transformer, the secondary coil has:
15. A step-down transformer decreases:
16. The transformer equation is Vₚ/Vₛ = Nₚ/Nₛ. If Nₚ = 100 and Nₛ = 500, and Vₚ = 220V, then Vₛ is:
17. A solenoid behaves like a magnet with:
18. When a magnet is pushed into a solenoid, the induced current:
19. An alternating current produces a magnetic field that:
20. The core material in an electromagnet should have:
21. Eddy currents in a transformer core cause:
22. In a generator, mechanical energy is converted to:
23. The ideal transformer equation for power is:
24. The magnetic field inside a long solenoid is:
25. When the switch in a circuit with an electromagnet is suddenly opened, the magnetic field: