Physics 5054 · O Level · The transformer

The transformer — practice question

A transformer with $100\%$ efficiency has a primary voltage input of $600\,\text{V}$ and a secondary voltage output of $240\,\text{V}$. The secondary coil is connected to a resistor with resistance $120\,\Omega$. What is the power dissipated in the resistor and what is the current in the primary coil?

  • Apower $120\,\text{W}$, current $0.20\,\text{A}$
  • Bpower $120\,\text{W}$, current $5.0\,\text{A}$
  • Cpower $480\,\text{W}$, current $0.80\,\text{A}$
  • Dpower $480\,\text{W}$, current $1.3\,\text{A}$

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