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JAMB Physics 2007 Question 28

Question 28

Thermal Expansion

The ratio of the coefficient of linear expansion of two metals α1/α2 is 3:4. If, when heated through the same temperature change, the ratio of the increase in lengths of the two metals, e1/e2 is 1:2, the ratio of the original lengths is l1/l2

  1. A.2/3
  2. B.8/3
  3. C.3/8
  4. D.3/2
Show the answer and explanation

Answer: A (2/3)

Explanation

Expansion e = αlΔθ with the same Δθ, so e1/e2 = (α1/α2)(l1/l2). 1/2 = (3/4)(l1/l2), so l1/l2 = 2/3.