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NEET PHYSICSELECTROMAGNETIC WAVESEasy

Question

A capacitor of capacitance CC is connected across an AC source of voltage VV, given by; V=V0sinωtV=V_0 \sin \omega t. The displacement current between the plates of the capacitor would then be given by:

A

Id=V0ωCsinωtI_d=\frac{V_0}{\omega C}\sin \omega t

B

Id=V0ωCsinωtI_d=V_0 \omega C \sin \omega t

C

Id=V0ωCcosωtI_d=V_0 \omega C \cos \omega t

D

Id=V0ωCcosωtI_d=\frac{V_0}{\omega C}\cos \omega t

Step-by-Step Solution

The displacement current (IdI_d) inside the capacitor is equal to the conduction current (II) flowing in the connecting wires.

  1. Charge on Capacitor: The charge qq on the capacitor at any time tt is given by q=CVq = CV. Substituting the given voltage V=V0sinωtV = V_0 \sin \omega t: q=C(V0sinωt)q = C(V_0 \sin \omega t)

  2. Calculate Current: The current is the rate of change of charge. Id=dqdt=ddt(CV0sinωt)I_d = \frac{dq}{dt} = \frac{d}{dt}(C V_0 \sin \omega t) Id=CV0ddt(sinωt)I_d = C V_0 \frac{d}{dt}(\sin \omega t) Id=CV0(ωcosωt)I_d = C V_0 (\omega \cos \omega t) Id=V0ωCcosωtI_d = V_0 \omega C \cos \omega t

Therefore, the displacement current is V0ωCcosωtV_0 \omega C \cos \omega t.

Exam Context & Concepts Covered

This question aligns with the NEET PHYSICS syllabus, specifically targeting concepts from ELECTROMAGNETIC WAVES. Mastering this topic is crucial for scoring well in the upcoming medical entrance examinations. Solving conceptually related problems will help you understand the nuances of these concepts and improve your problem-solving speed.

PHYSICSELECTROMAGNETIC WAVEScapacitorcapacitanceconnectedacrosssource

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