Electromagnetic Induction and Alternating Current — Flashcards
NIOS · Class 12 · Physics
35 flashcards for Electromagnetic Induction and Alternating Current (NIOS Class 12 Physics) to test yourself on key terms and facts.
Interactive on Super Tutor
Studying Electromagnetic Induction and Alternating Current? Get the full interactive chapter.
Quizzes, flashcards, AI doubt-solver and a step-by-step study plan — built for flashcards and more.
Free trial, no card needed.

One of 26 illustrations for Electromagnetic Induction and Alternating Current in Super Tutor — alongside flashcards, concept maps and practice questions.
State Faraday's Law of Electromagnetic Induction. Write the formula for a coil with N turns.
Answer
Faraday's Law: The magnitude of the induced emf in a loop is equal to the rate of change of magnetic flux linked with it. For a single loop: |ε| = dΦ_B / dt For a coil with N turns: |ε_total| = N × …
State Lenz's Law. How is it combined with Faraday's Law mathematically?
Answer
Lenz's Law: When a current is induced in a conductor, the direction of the induced current is such that its magnetic effect OPPOSES the change (in flux) that induced it. Combined Faraday-Lenz Law: ε …
A 75-turn circular coil of radius 35 mm has its axis parallel to a uniform magnetic field. The field changes from 25 mT to 50 mT in 250 ms. Find the induced emf.
Answer
Given: N = 75 turns, R = 35 mm = 0.035 m B₁ = 25 mT = 0.025 T, B₂ = 50 mT = 0.050 T t = 250 ms = 0.250 s Rate of change of field: dB/dt = (B₂ − B₁)/t = (0.050 − 0.025)/0.250 = 0.10 T/s Flux per turn…
What are Eddy Currents? Why are they considered undesirable in many devices, and how are they minimised?
Answer
Eddy Currents: When a solid conductor (like a metal sheet or plate) is placed in a changing magnetic field, induced closed loops of current are set up inside the bulk of the conductor. These are calle…
Define Self-Inductance. Write the formula relating magnetic flux to self-inductance and the formula for induced back emf.
Answer
Self-Inductance (L): It is the property of a coil by which it opposes any change in the current flowing through it. The magnetic flux linked with the coil is proportional to the current. Formula: Φ =…
Derive the formula for the self-inductance of a solenoid of length ℓ, cross-sectional area A, and N turns.
Answer
Step-by-Step Derivation: Step 1 – Magnetic field inside solenoid: Using Ampere's Law: B = μ₀ × n × I where n = N/ℓ (turns per unit length) Step 2 – Total magnetic flux through N turns: Φ = N × B × A…
A solenoid is 1 m long, 20 cm in diameter, and contains 10,000 turns of wire. A current of 2.5 A is reduced to zero in 1.0 ms. Calculate the magnitude of the back emf.
Answer
Given: ℓ = 1 m, diameter = 20 cm → radius = 0.10 m A = π × (0.10)² = π × 0.01 = 3.14 × 10⁻² m² N = 10,000 turns I₁ = 2.5 A, I₂ = 0 A, t = 1.0 ms = 1.0 × 10⁻³ s Step 1 – Find Self-Inductance: L = μ₀ N…
Define Mutual Inductance. Write the formula for induced emf in the secondary coil due to changing current in the primary coil.
Answer
Mutual Inductance (M): When two coils are placed close to each other, a changing current in coil A (primary) causes a changing flux through coil B (secondary), inducing an emf in B. This property is c…
+27 more flashcards
Practise AllFrequently Asked Questions
What are the important topics in Electromagnetic Induction and Alternating Current for NIOS Class 12 Physics?
How many flashcards are available for Electromagnetic Induction and Alternating Current?
How should I revise Electromagnetic Induction and Alternating Current for the NIOS Class 12 board exam?
Sources & Official References
Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.
More resources for Electromagnetic Induction and Alternating Current
Practice Quiz
Test yourself with a quick quiz
Important Questions
Exam-style questions with answers
Revision Notes
Key points for last-minute revision
Formula Sheet
The chapter's formulas in one place
Chapter Summary
Understand the chapter at a glance
Concept Maps
See how topics connect
Study Plan
Step-by-step plan for this chapter
Syllabus
What topics to cover
For serious students
Get the full Electromagnetic Induction and Alternating Current chapter — start free.
Quizzes, flashcards, an AI doubt solver and a study plan for NIOS Class 12 Physics. Free to start, no card needed.