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⚛️ Physics  ·  Alternating Current  ·  NEET & JEE

The frequency of AC supplied in India is:

Answer: 50 Hz.

  • A 50 Hz
  • B 60 Hz
  • C 100 Hz
  • D 25 Hz

Correct answer: A. 50 Hz

Explanation: India uses 50 Hz AC supply at 230 V (RMS). The USA uses 60 Hz at 120 V.

V and I Phase Relationships in AC CircuitsPure Inductor: I lags V by 90°VIPure Capacitor: I leads V by 90°VIMemory aid "ELI the ICE man": in an inductor (L) E(V) leads I; in a capacitor (C) I leads E(V)For a pure resistor, V and I stay perfectly in phase (no lag or lead at all)

In a pure inductor the current lags the voltage by 90° (energy is briefly stored in the magnetic field before current responds); in a pure capacitor the current leads the voltage by 90° (current must flow to build up charge before voltage rises) - the mnemonic "ELI the ICE man" keeps these straight.

Concept context

AC circuits, impedance, LCR series circuit, resonance, transformers, and power factor.

Read the full Alternating Current notes →