JAMB Physics 1979 Question 34

Question 34

Thermal Expansion

Consider a thick glass tumbler and a thin glass tumbler which are made of the same kind of glass. Some hot liquid is poured into them. Which of the following statements is correct?

  1. A.The thick tumbler is less likely to crack because it is stronger
  2. B.The thick tumbler is less likely to crack because it insulates the heat better, glass being a poor conductor of heat.
  3. C.Both tumblers are equally likely to crack because they are made of the same kind of glass.
  4. D.The thick tumbler is more likely to crack because uneven expansion persists for a longer time within the thicker glass
  5. E.The thick tumbler is more likely to crack because it is heavier.
Show the answer and explanation

Answer: D (The thick tumbler is more likely to crack because uneven expansion persists for a longer time within the thicker glass)

Explanation

Glass conducts heat poorly, so in thick glass the inside surface expands while the outside stays cool. This uneven expansion sets up strains that crack it; thin glass warms through quickly and evenly.