Question

The water vapor in the atmosphere from the given plant sample is measured by
A. Auxanometer
B. Psychrometer
C. Osmometer
D. Photometer

Answer 1

Hint: Plants may release water vapour into the air. This released water vapor amount can be measured by one type of hygrometer.

Complete answer: Plants can provide water vapor in the atmosphere it is measured by an instrument called a psychrometer.
It is a subtype of hygrometers which can measure humidity levels in the atmosphere.
There are two types of thermometers used in the instrument viz. a dry-bulb thermometer and a wet-bulb thermometer.
Dry bulb thermometer –as the name suggests has to be kept dry and so it is exposed to air.
A wet-bulb thermometer can be exposed to liquid substances.
Then a comparison between the readings obtained from these two thermometers can be determined to find out humidity/water vapor released.

So, the correct option is B. Psychrometer

Note: The water vapor released into the atmosphere is different from the rate of transpiration is proportional to water-uptake by roots. This measurement is indirect because some water is used in photosynthetic processes. However, the transpiration rate can be measured by Ganong’s Photometer. Osmometer measures the osmotic pressure of a solution and an auxanometer can measure the increased height of a plant.