WAEC Physics 2016 Paper

Concept:Temperature is directly proportional to the mercury length between the ice and steam points.Explanation:The mercury length at the ice point is $4\, \text{cm}$, corresponding to $0^\circ\text{C}$.The mercury length at the steam point is $29\, \text{cm}$, corresponding to $100^\circ\text{C}$.The total change in length is $29 - 4 = 25\, \text{cm}$, which represents $100^\circ\text{C}$.When the mercury level is at $9\, \text{cm}$, the rise above the ice point is:$9 - 4 = 5\, \text{cm}$.Now apply the proportion:$\text{Temperature} = \frac{5}{25} \times 100 = 20^\circ\text{C}$.Therefore, the temperature at the $9\, \text{cm}$ mark is $20^\circ\text{C}$.Answer:$20^\circ\text{C}$