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Question 31618
JEE Physics · Hard

Current Electricity: Relaxation Time MCQ

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Relaxation TimeHardQuestion 31618

Question

Relaxation time τ in free electron theory is the average time between:
  1. A
    Two current pulses
  2. B
    Two collisions of an electron with the lattice
    Correct
  3. C
    Two voltage reversals
  4. D
    Two charge transfers

Correct answer

Two collisions of an electron with the lattice

Explanation

τ is the mean free time between electron-lattice scattering events. Resistivity ρ = m/(ne²τ). Shorter τ (more scattering) means higher resistivity.

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