Physics 9702 · AS & A Level · Practical circuits

Practical circuits — practice question

For an ideal diode, the resistance is zero when it is forward biased and infinite when it is reverse biased. The diode is placed in series with a $2\,\Omega$ resistor across the terminals of a source with electromotive force (e.m.f.) $3\,\text{V}$ and internal resistance $1\,\Omega$, as shown. A voltmeter with very high resistance is connected across the diode and resistor. Which row shows the voltmeter readings for the two possible ways of connecting the diode?

  • Aforward biased: $1\,\text{V}$, reverse biased: $3\,\text{V}$
  • Bforward biased: $2\,\text{V}$, reverse biased: $0\,\text{V}$
  • Cforward biased: $2\,\text{V}$, reverse biased: $3\,\text{V}$
  • Dforward biased: $3\,\text{V}$, reverse biased: $0\,\text{V}$

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