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JAMB Physics 1979 Question 14

Question 14

Temperature and Thermometers

The heights of the mercury thread in a mercury-in-glass thermometer when in melting ice and then in steam are 3 cm and 18 cm respectively. At a temperature of 60°C the height would be

  1. A.7.5 cm
  2. B.9 cm
  3. C.10.8 cm
  4. D.12 cm
  5. E.12.6 cm
Show the answer and explanation

Answer: D (12 cm)

Explanation

The 100 degrees span 18 − 3 = 15 cm. At 60°C the thread is 60% of the way up: 3 + 0.6 × 15 = 12 cm.