Zaymiey

⚛️ Physics  ·  Alternating Current  ·  NEET & JEE

A step-up transformer has 100 turns in the primary and 1000 in the secondary. If the primary voltage is 100 V, the secondary voltage (ideal transformer) is:

Answer: 1000 V.

  • A 10 V
  • B 100 V
  • C 110 V
  • D 1000 V

Correct answer: D. 1000 V

Explanation: V<sub>s</sub> = V<sub>p</sub>·(N<sub>s</sub>/N<sub>p</sub>) = 100·(1000/100) = 1000 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 →