Engineering
Physics
Thermal Expansion
Question

A crystal has a coefficient of expansion 13 × 10 – 9 in one direction and 231 × 10– 9 in every direction at right angles to it. Then the cubical coefficient of expansion is :

4.62 × 10– 7

4.75 × 10– 7

2.44 × 10– 7

2.57 × 10 – 7 s

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Solution

The cubical coefficient of expansion (γ) is the sum of the linear coefficients in three perpendicular directions. Given α1 = 13 × 10–9 and α2 = α3 = 231 × 10–9, the formula is:

γ=α1+α2+α3

Substituting the values: γ = (13 + 231 + 231) × 10–9 = 475 × 10–9 = 4.75 × 10–7.

Final Answer: 4.75 × 10–7