Reliability

For a failure mechanism with an activation energy of 0.7 eV, approximately what is the Arrhenius acceleration factor of 125 °C relative to 55 °C? (Boltzmann constant 8.6×10⁻⁵ eV/K)

  1. AAbout 2
  2. BAbout 80
  3. CAbout 8000
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Answer: B. About 80

The acceleration factor is exp{(Ea/k)(1/T1 − 1/T2)}. With T1 = 328 K and T2 = 398 K, (0.7 / 8.6×10⁻⁵) × (1/328 − 1/398) ≈ 8140 × 0.000536 ≈ 4.4, and exp(4.4) ≈ 80. A 1000-hour test at 125 °C is thus equivalent to about 80,000 hours at 55 °C.

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