WAEC - Physics (2020 - No. 15)
Two identical cups containing the same volume of water at 45°C and 5°C, are left in a room at 25°C. Which of the following graphs correctly illustrates the variation of temperature with time?
A
B
C
D
Shpjegimi
The cup containing water at 45∘C loses heat to the room since temperature of the room is lower than its temperature, hence its temperature reduces gradually, the cup containing water at 5∘C gains heat from the room since its temperature is lower than that of the room. hence, its temperature increases gradually, the lines are curved because as the temperature of the water changes the temperature difference between the water and surroundings also changes