Question

The figure given below represents an experimental setup with a weighing machine to demonstrate a particular process in plants. The experimental setup was placed in bright sunlight. Study the diagram and answer the following questions.

(a) Define the above mentioned process.
(b) When the weight of the test tubes A and B is taken before and after the experiment, what change is observed? Justify.
(c) What is the purpose of keeping the test tube B in the experimental setup?

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Answer 1

(a) Transpiration is the loss of water in the form of water vapour from the leaves and other aerial parts of the plant.

(b) Weight of test tube A is taken before the experiment was more when compared to its weight after the experiment. Because water from test tube A has evaporated due to transpiration.

Weight of test tube B is taken before and after the experiment remains the same because no loss of water occurs in test tube B. This is because oil is putting on the test tube.

(c) The purpose of keeping the test tube B in the experimental setup this makes the observation of the change in test tube A easy.