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JAMB Physics 1987 Question 18

Question 18

Thermal Expansion

The length of a side of a metallic cube at 20°C is 5.0 cm. Given that the linear expansivity of the metal is 4.0 × 10−5 K−1, find the volume of the cube at 120°C.

  1. A.126.50 cm3
  2. B.126.25 cm3
  3. C.126.00 cm3
  4. D.125.00 cm3.
Show the answer and explanation

Answer: A (126.50 cm3)

Explanation

Cubic expansivity ≈ 3 × 4 × 10−5 = 1.2 × 10−4 K−1. V = 125 × (1 + 1.2 × 10−4 × 100) = 126.5 cm3.