Magnetic Effects of Electric Current in Science

Updated on May 31, 2025 | By Learnzy Academy

When an electric current flows through a conductor (like a wire), it produces a magnetic field around it. This is called the magnetic effect of electric current.

Key Concepts:

  • Magnetic Field Around a Wire:-
    • Current in a wire produces a magnetic field.
    • Right-Hand Thumb Rule helps determine the direction of the field.
  • Solenoid:- 
    • A coil of wire that creates a strong magnetic field when current flows through it. It behaves like a magnet.
  • Electromagnet:-
    • A temporary magnet created by passing current through a coil around an iron core.
  • Force on a Current-Carrying Conductor: -
    • A wire carrying current in a magnetic field experiences a force.
    • Fleming's Left-Hand Rule determines the direction of the force.

Applications:

  • Electric Motors:Use the force on current-carrying conductors in a magnetic field to produce motion.
  • Electromagnets:Used in devices like cranes to lift heavy magnetic materials.

 

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List of question on "Magnetic Effects of Electric Current"

  1. Imagine that you are sitting in a chamber with your back to one wall. An electron beam, moving horizontally from back wall towards the front wall, is deflected by a strong magnetic field to your right side. What is the direction of magnetic field?
  2. When is the force experienced by a current–carrying conductor placed in a magnetic field largest?
  3. List two methods of producing magnetic fields.
  4. At the time of short circuit, the current in the circuit (a) reduces substantially. (b) does not change. (c) increases heavily. (d) vary continuously
  5. Which of the following correctly describes the magnetic field near a long straight wire? (a) The field consists of straight lines perpendicular to the wire. (b) The field consists of straight lines parallel to the wire. (c) The field consists of radial lines originating from the wire. (d) The field consists of concentric circles centred on the wire
  6. List the properties of magnetic field lines.
  7. Why does a compass needle get deflected when brought near a bar magnet?
  8. Define the term induced electric current.
  9. State the effect of a magnetic field on the path of a moving charged particle.
  10. Write the frequency of alternating current (AC) in India. How many times per second it changes its direction?
  11. Explain why alternating current is preferred over direct current for transmission over long distances.
  12. Define alternating current and direct current.
  13. Mention the frequency of D.C that is given by a cell.
  14. Alternating current has a frequency of 50 Hz. What is meant by this statement? How many times does it change its direction in one second? Give reason for your answer
  15. Mention and explain the function of an earth wire. Why it is necessary to earth metallic appliances?
  16. Fuse acts like a watchman in an electric circuit. Justify this statement.
  17. List three methods of producing a magnetic field.
  18. What precaution should be taken to avoid the overloading of the domestic electric circuit?
  19. Electric appliances like electric -press, toaster, fans etc are connected to electric mains through three-pin plug. Why?
  20. What is the function of an earth wire? Why is it necessary to earth metallic casing of electric appliances?
  21. A current-carrying straight conductor is placed in the east-west direction. What will be the direction of the force experienced by this conductor due to earth’s magnetic field? How will this force get affected?
  22. Why is the earth pin thicker and longer than the live and the neutral pins?
  23. When does an electric short circuit occur?
  24. When is the force experienced by a current-carrying conductor placed in magnetic field largest?
  25. State the principle of an electric generator.
  26. What is the role of the split ring in an electric motor?
  27. State and define S.I unit of magnetic field?
  28. What is an electromagnet? Write two uses of an electromagnet?
  29. State the factors on which strength of magnetic field at a point due to a current carrying conductor depends?
  30. What is electric fuse? Where is it connected in a circuit?
  31. Name and state rule used to determine the direction of magnetic field produced around a straight conductor carrying current?
  32. Why do not two magnetic field lines intersect each other?
  33. Write two ways to induce current in a coil?
  34. Why does a compass needle deflect when brought near a bar magnet?
  35. State two properties of magnetic lines of force?
  36. In Faradays experiment if instead of moving the magnet towards the coil we move the coil towards the magnet. Will there be any induced current? Justify your answer. Compare the two cases.
  37. If field lines of a magnetic field are crossed at a point, what does it indicate ?
  38. What is meant by magnetic field?