CUET · PHYSICS · PYQ PAPER 2023

Displacement current (\( i_{d} \)) = \( \epsilon_{0} \frac{d\phi_{E}}{dt} \)
Where symbols have their usual meanings.
Which of the following options gives correct equation for displacement current ?

A \( i_{d} = \epsilon_{o} \frac{d(BA)}{dt} \)
B \( i_{d} = A \epsilon_{o} \frac{dE}{dt} \)
C \( i_{d} = q A \epsilon_{o} \frac{dE}{dt} \)
D \( i_{d} = \frac{A \epsilon_{o}}{q} \frac{dE}{dt} \)

Verified Solution

Answer & Solution

Correct Answer

(B) \( i_{d} = A \epsilon_{o} \frac{dE}{dt} \)

Step-by-step Solution

Detailed explanation

\( \phi_{E} = EA \) \( i_{d} = \epsilon_{0} \frac{d(EA)}{dt} \) \( i_{d} = A \epsilon_{0} \frac{dE}{dt} \)

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

Same subject

Match List I with List II

List I	List II
A. Rod rotated in uniform magnetic field	I. \( e = e_{0} \sin(\omega t) \)
B. Coil rotated in uniform magnetic field	II. \( e = Blv \)
C. Rod moved with linear velocity \( v \)	III. constant (for motional emf at constant \( v \))
D. Rectangular coil moved in magnetic field	IV. \( e = \frac{B\omega l^{2}}{2} \)

Choose the correct answer from the options given below:

CUET 2023 Hard

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