JEE Main 2023 · 1 February · morning · Single correct · +4 / −1
Match List - I with List - II :
Choose the correct answer from the options given below :
| List I | List II | ||
|---|---|---|---|
| A. | AC generator | I. | Presence of both L and C |
| B. | Transformer | II. | Electromagnetic Induction |
| C. | Resonance phenomenon to occur | III. | Quality factor |
| D. | Sharpness of resonance | IV. | Mutual Induction |
- (a) A-II, B-I, C-III, D-IV
- (b) A-IV, B-III, C-I, D-II
- (c) A-II, B-IV, C-I, D-III
- (d) A-IV, B-II, C-I, D-III
Answer and solution
Answer (c) A-II, B-IV, C-I, D-III
Solution
Physics sir · 3 steps
Both the generator and the transformer use induction. Ask which one needs a second coil.
- Generator versus transformer. In an AC generator a single coil rotates in a magnetic field, so the changing flux through it induces an emf. That is electromagnetic induction. A transformer has no moving part: the changing current in the primary coil induces an emf in a separate secondary coil, which is mutual induction.
- Resonance and its sharpness. Resonance happens when X_L = X_C, so the circuit must contain both an inductor and a capacitor. How sharply the current peaks at resonance is measured by the quality factor Q = (ω₀ L)/R.
List I Matches Reason A. AC generator II, Electromagnetic induction a rotating coil cuts a changing flux B. Transformer IV, Mutual induction the primary induces an emf in the secondary C. Resonance to occur I, Both L and C needs X_L = X_C D. Sharpness of resonance III, Quality factor higher Q gives a sharper peak - So. The matching is A-II, B-IV, C-I, D-III, which is option (c).
The idea to keep. Every induction device runs on Faraday's law. Call it mutual induction only when the emf appears in a second coil because the current changes in the first one.
Answer from the NTA final answer key. Solution by PrepWiser.