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    Question

    Which of the following is/are correct? 1. 

    Displacement current can exist in vacuum 2.  Magnetic field can exist without electric field 3.  Changing electric field necessarily produces magnetic field 4.  Displacement current is not a real current because it involves no charge transport
    A 1, 2, and 3 Correct Answer Incorrect Answer
    B 1, 2, 4 Correct Answer Incorrect Answer
    C 2 and 4 Correct Answer Incorrect Answer
    D All of the above Correct Answer Incorrect Answer

    Solution

    • Displacement current can exist in vacuum:
      True. Displacement current was introduced by Maxwell to correct Ampere’s law in cases where there is a changing electric field but no conduction current, like in a capacitor or even in free space (vacuum). Hence, displacement current can exist in a vacuum.
    • Magnetic field can exist without electric field:
      True. A static magnetic field (like the field around a bar magnet) can exist without any associated electric field. Electric and magnetic fields are linked when changing with time, but a static magnetic field can independently exist.
    • Changing electric field necessarily produces magnetic field:
      True. According to Maxwell’s equations, a time-varying electric field produces a magnetic field. This is the principle behind electromagnetic wave generation.
    • Displacement current is not a real current because it involves no charge transport:
      True. Displacement current does not involve actual movement of charges; it is a mathematical term representing the effect of a changing electric field, not a flow of charges like conduction current.
    Thus, all four statements are correct .

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