On a rainy day—
- AThe dry bulb and wet bulb thermometers show the same reading.
- BThe dry bulb thermometer shows a lower reading than the wet bulb thermometer.
- CThe dry bulb thermometer shows a higher reading than the wet bulb thermometer.
- DMore than one of the above
- ENone of the above
Show answer and explanation
Correct answers: (a) The dry bulb and wet bulb thermometers show the same reading. or (c) The dry bulb thermometer shows a higher reading than the wet bulb thermometer.
Explanation
The dry-bulb thermometer reads the air temperature. The wet bulb is cooled by evaporation, so it normally reads lower; the drier the air, the bigger the gap.
On a rainy day the air is nearly saturated, so little water evaporates and the two read almost the same. The book gives (c), that the dry bulb still reads higher.
On a rainy day the air is nearly saturated, so the two thermometers read almost the same (a); the book gives (c). Both are accepted here.