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Question 30891
JEE Physics · Hard

Elasticity, Thermal Expansion, Calorimetry and Heat Transfer: Thermal Expansion Advanced MCQ

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Thermal Expansion AdvancedHardQuestion 30891

Question

Invar (Fe-Ni alloy) is used in precision instruments because:
  1. A
    It is very hard
  2. B
    It has extremely low coefficient of thermal expansion
    Correct
  3. C
    It is non-magnetic
  4. D
    It has high thermal conductivity

Correct answer

It has extremely low coefficient of thermal expansion

Explanation

Invar has α ≈ 1.2×10⁻⁶ /°C — about 10× lower than most metals — making it ideal for clocks, optical instruments, and standards.

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