electromagnetic-waves Question 14
Question: Q. 1. How does Ampere-Maxwell law explain the flow of current through a capacitor when it is being charged by a battery? Write the expression for the displacement current in terms of the rate of change of electric flux.
U] [Delhi I, II, III 2017]
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Solution:
Ans. Explanation of flow of current through capacitor1 Expression for displacement current. 1 During charging, electric flux between the plates of capacitor keeps on changing; this results in the production of a displacement current between the plates.
$$ I_{d}=\varepsilon_{0} \frac{d \phi_{E}}{d t}\left(I_{d}=\varepsilon_{0} A \frac{d E}{d t}\right) $$
[CBSE Marking Scheme, 2017]
AI Q. 2. How is electromagnetic wave produced ? Draw a sketch of a plane EM wave propagating along $X$-axis depicting the directions of the oscillating electric and magnetic fields.
U [Delhi Comptt. I, II, III 2017] Ans. Production of EM waves. 1 Diagram depicting the oscillating electric and magnetic fields.
Electromagnetic waves are produced due to oscillating/accelerating charged particles.
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Detailed Answer :
(i) Production of EM wave :
Electromagnetic waves consist of both electric and magnetic fields travelling through empty space with the speed of light $c$. These waves oscillate in perpendicular planes with respect to each other and are in phase. An electromagnetic wave can be created by accelerating charges; moving charges back and forth, producing oscillating electric and magnetic fields. When the accelerating charged particle moves with acceleration, both magnetic and electric fields change continuously which lead to production of electromagnetic waves.
(ii) Diagram : Try yourself, Similar to Q. 3, Very Short Answer Type Questions.
