Electromagnetic Waves
Telangana Open School (TOSS) · Class 12 · Physics
Flashcards for Electromagnetic Waves — Telangana Open School (TOSS) Class 12 Physics. Quick Q&A cards covering key concepts, definitions, and formulas.
Interactive on Super Tutor
Studying Electromagnetic Waves? Get the full interactive chapter.
Quizzes, flashcards, AI doubt-solver and a step-by-step study plan — built for flashcards and more.
1,000+ Class 12 students started this chapter today
What is displacement current? Why is it necessary?
Answer
Displacement current is a current due to a changing electric field in space or capacitor gap, given by $ i_d = \varepsilon_0 \frac{d\phi_E}{dt} $. It is necessary to maintain continuity of current in …
State the Ampere-Maxwell law.
Answer
The Ampere-Maxwell law is: $ \oint \vec{B} \cdot \vec{dl} = \mu_0 (i_c + i_d) = \mu_0 i_c + \mu_0 \varepsilon_0 \frac{d\phi_E}{dt} $. It states that magnetic fields are produced by both conduction cur…
A parallel plate capacitor is being charged by a current of 1.5 A. What is the displacement current between the plates?
Answer
Displacement current $ i_d $ equals the conduction current in the wire. Given: $ i_c = 1.5 \, \text{A} $. Therefore, $ i_d = 1.5 \, \text{A} $.
How does a changing electric field produce a magnetic field?
Answer
According to Maxwell, a time-varying electric field generates a magnetic field, just as a current does. This is the displacement current effect. For example, during capacitor charging, the changing el…
An EM wave has electric field amplitude $ E_0 = 120 \, \text{N/C} $. Find the magnetic field amplitude.
Answer
Use $ B_0 = \frac{E_0}{c} $. $ c = 3 \times 10^8 \, \text{m/s} $. Step 1: $ B_0 = \frac{120}{3 \times 10^8} = 4 \times 10^{-7} \, \text{T} $. Answer: $ 4 \times 10^{-7} \, \text{T} $.
What is the speed of electromagnetic waves in vacuum?
Answer
The speed is $ c = \frac{1}{\sqrt{\mu_0 \varepsilon_0}} = 3 \times 10^8 \, \text{m/s} $. This is the speed of light, confirming that light is an EM wave.
An EM wave propagates in the x-direction with $ E = 8.1 \, \text{V/m} $. Find $ B $ at that point.
Answer
Use $ B = \frac{E}{c} $. $ c = 3 \times 10^8 \, \text{m/s} $. Step 1: $ B = \frac{8.1}{3 \times 10^8} = 2.7 \times 10^{-8} \, \text{T} $. Answer: $ 2.7 \times 10^{-8} \, \text{T} $.
Write the expressions for electric and magnetic fields in an EM wave propagating along z-axis.
Answer
Electric field: $ E_x = E_0 \sin(kz - \omega t) $. Magnetic field: $ B_y = B_0 \sin(kz - \omega t) $. Both are perpendicular to each other and to the direction of propagation.
+22 more flashcards available
Practice AllFrequently Asked Questions
What are the important topics in Electromagnetic Waves for Telangana Open School (TOSS) Class 12 Physics?
How to score full marks in Electromagnetic Waves — Telangana Open School (TOSS) Class 12 Physics?
How many flashcards are available for Electromagnetic Waves?
Sources & Official References
Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.
More resources for Electromagnetic Waves
Practice Quiz
Test yourself with a quick quiz
Important Questions
Practice with board exam-style questions
Revision Notes
Key points for last-minute revision
Formula Sheet
All formulas in one place
Chapter Summary
Understand the chapter at a glance
Concept Maps
See how topics connect visually
Study Plan
Step-by-step plan to ace this chapter
Syllabus
What topics to cover
NCERT Solutions
Every textbook question solved step by step
For serious students
Get the full Electromagnetic Waves chapter — for free.
Quizzes, flashcards, AI doubt-solver and a step-by-step study plan for Telangana Open School (TOSS) Class 12 Physics.