Maxwell argued that not only an electric current but also a time-varying electric field produces magnetic field. While applying the Ampere’s circuital law to find magnetic field at a point outside a capacitor connected to a time-varying current, Maxwell noticed an inconsistency in the Ampere’s circuital law. To remove this inconsistency he suggested the existence of an additional current called the “DISPLACEMENT CURRENT”
DISPLACEMENT CURRENT
The current changing electric field or electric movement is called displacement current.
The current carried by the conductors due to flow of charges is called conduction current.
Questions on Displacement Current
Q. 1: What is the S.I. unit of displacement current?
Ans : the SI unit of displacement current is Ampere (A)
Q. 2: How does the displacement current arise?
Ans: Displacement current arises due to varying electromotive force.
Q. 3: What is the output of a capacitor connected to displacement current?
Ans: Zero
Q. 4: What is displacement current?
Ans: The current due to the changing electric field is called displacement current.
Q. 5: Does the displacement current satisfy the property of continuity?
Ans: Yes, the sum of displacement and conduction current remains constant along the closed path.
Q. 6: Write the expression for the displacement current.
Ans :
Q. 7: What is the magnitude of displacement current in case of steady electric fields in a conducting wire?
Ans : Zero
Q. 8: What current does exists inside a capacitor?
Ans: The current that exists inside the capacitor is Displacement current.
Q. 9: State Ampere-Maxwell law
Ans: The line integral of the magnetic field around a closed loop is equal to μ0 times the sum of conduction current and displacement current.
Q. 10: Why was the concept of displacement current introduced?
Ans: Displacement current was introduced to the current in terms of Ampere circuit law to make it logically consistent.
Q. 11: Distinguish between conduction current and displacement current?
Ans: Conduction current is due to the flow of electrons in a circuit. It exists even if electrons flow at a uniform rate.
Displacement current is due to the time-varying electric field. It does not exist under steady conduction.
Q. 12: What is the magnitude of displacement current in case of steady electric fields in a conducting wire? Explain.
Ans: The magnitude of displacement current in case of steady electric fields in a conducting wire is zero since the electric field E does not change with time.
Q. 13: How does the concept of displacement current associated in the behavior of electric and magnetic fields?
Ans: According to Faraday’s law of electromagnetic induction, a time-varying magnetic field induces an emf, According to Maxwell, an electric field sets up a current and hence a magnetic field. Such a current is called displacement current. It follows that a time-varying electric field produces a magnetic field and vice-versa. Hence, the behavior of the electric and magnetic field is symmetric.
Hope you have understood about Displacement current, Ampere-Maxwells law, Displacement current formula, displacement current equation, its significance, terms, Units along with practice questions.
