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⚛️ Physics  ·  Current Electricity  ·  NEET & JEE

Which of the following is a non-ohmic device whose V-I graph is not a straight line?

Answer: a semiconductor diode.

  • A a metal wire at constant temperature
  • B a semiconductor diode
  • C a carbon film resistor
  • D a length of nichrome wire

Correct answer: B. a semiconductor diode

Explanation: A semiconductor diode conducts very differently in forward and reverse bias, so its V-I graph is non-linear and direction-dependent, a limitation of Ohm's law.

SeriesbatteryR1R2I (same in R1, R2)ParallelbatteryR1R2I1I2

In series, the same current flows through both resistors; in parallel, the current splits between branches and the voltage across each resistor is the same.

Concept context

Ohm's law, resistors, Kirchhoff's laws, Wheatstone bridge, and cells.

Read the full Current Electricity notes →