alleryStart learning →For an ideal capacitor in AC, capacitive reactance:
- 1/(ωC)
- C / ω
- ωC
- ω²C
Show answer and solution
Correct answer: A. 1/(ωC)
X_C = 1/(ωC).
Current leads voltage by 90°.
Reactance decreases with frequency — capacitors pass high frequencies, block DC.
JEECUP (UP Polytechnic) Electromagnetic Induction — practice questions — page 2
Explore 53 free Electromagnetic Induction questions in JEECUP (UP Polytechnic) Physics. Open each question or exercise to read its content, reference answers and available explanation.
Practise Electromagnetic Induction with Quill →Electromagnetic Induction questions and exercises with answers
Showing questions 31–53 of 53.
For an ideal capacitor in AC, capacitive reactance:Read the answer and worked solution →In an LCR series AC circuit, impedance:Read the answer and worked solution →Resonance in series LCR circuit occurs when:Read the answer and worked solution →RMS value of an AC voltage with peak V₀:Read the answer and worked solution →Average power in AC LCR circuit:Read the answer and worked solution →A 100-turn coil of area 200 cm² is rotated at 50 rev/s in a field of 0.05 T. Peak EMF:Read the answer and worked solution →A solenoid has L = 2 H. Current decreases from 5 A to 1 A in 0.1 s. EMF induced:Read the answer and worked solution →In a step-down transformer with 1000:100 turn ratio (primary:secondary), 220 V input, 1 A secondary current. Primary current (ideal):Read the answer and worked solution →Quality factor Q for series LCR at resonance:Read the answer and worked solution →Two coils with self-inductances L₁ = 4 H, L₂ = 9 H. Maximum possible mutual inductance:Read the answer and worked solution →Energy density of magnetic field B in vacuum:Read the answer and worked solution →In an LR circuit with V = 12 V, R = 4 Ω, L = 2 H, current after t = 0.5 s:Read the answer and worked solution →A capacitor C in series with inductor L (LC circuit) oscillates with frequency:Read the answer and worked solution →In AC circuit with only inductor, average power consumed over one full cycle:Read the answer and worked solution →For an AC generator with EMF ε(t) = ε₀ sin(ωt), the RMS EMF:Read the answer and worked solution →Phase difference between voltage and current in pure capacitor in AC:Read the answer and worked solution →Inductive reactance increases linearly with frequency. At f = 50 Hz, X_L = 100 Ω. At f = 200 Hz, X_L =Read the answer and worked solution →NEET · Physics · Lenz's Law — EMF SignRead the answer and worked solution →Faraday + Lenz — true or false?Read the answer and worked solution →Sort what each inductance needsRead the answer and worked solution →Knock out the false induction claimsRead the answer and worked solution →Catch the false line on inductionRead the answer and worked solution →Match each quantity to its unitRead the answer and worked solution →
Worked practice questions
In an LCR series AC circuit, impedance:
- R × X_L
- R + L + C
- sqrt(R² + (X_L - X_C)²)
- R + X_L + X_C
Show answer and solution
Correct answer: C. sqrt(R² + (X_L - X_C)²)
Z = sqrt(R² + (X_L - X_C)²).
Magnitude of impedance phasor.
**Phase:** tan φ = (X_L - X_C)/R. Used to find current amplitude I₀ = V₀/Z.
Resonance in series LCR circuit occurs when:
- X_L + X_C = R
- X_L = X_C → ω = 1/sqrt(LC)
- R = 0
- L = C
Show answer and solution
Correct answer: B. X_L = X_C → ω = 1/sqrt(LC)
At resonance, X_L = ωL = 1/(ωC) = X_C.
So ω₀ = 1/sqrt(LC).
Z = R (minimum), current maximum, power factor = 1.
How to practise
- Choose a Electromagnetic Induction question and try to work out your answer.
- Open the question to check the correct answer and read its worked solution.
- Continue in the app for bite-sized lessons, explanations and review with Quill. You can start without creating an account.