English Medium कक्षा १० - CBSE Question Bank Solutions

Will the levels of biological magnification be different at different levels of the ecosystem?

 With the help of a food chain, explain how biological magnification of harmful chemicals can occur.

What is meant by bioconcentration of pesticides

Which common pesticide has accumulated in human body in considerable amounts?

What does garbage consist of?

Consider the following food chain

(i) Plants → Mice → Snakes → Hawks
(ii) Plants → Mice →Hawks
If energy available at the producer level in both the food chains is 100 J, in which case will hawks get more energy as food and by how much? Justify your answer.:

 Explain why, a food chain usually cannot have more than three or four steps.

Calculate the amount of energy that will be available to big fish in the following food chain, if 10,000 J of energy is available to small algae from the sun :
Small algae → Zooplankton → Fish → Big fish

Name and state the law given by Lindeman which tells us how much energy entering a particular trophic level of organisms is available for trasnsfer to the next higher trophic level.

How much energy will be available to hawks in the food chain comprising hawk, snake, paddy and mice, if 10,000 J of energy is available to paddy from the sun?

On what basis is a chemical equation balanced?

What provides the energy which then flows through a food chain?
(a) glucose
(b) oxygen
(c) respiration
(d) sunlight

In the food chain given below, if the amount of energy available at fourth trophic level is 5 kJ, what was the energy available at the producer level?
Grass → Grasshopper → Frog → Snake → Hawk
(a) 500 kJ
(b) 50 kJ
(c) 5000 kJ
(d) 5 kJ

Which of the following limits the number of trophic levels in a food chain?
(a) insufficient food supply from producer level
(b) decrease in energy at higher trophic levels
(c) increase in the number of organisms at higher trophic levels
(d) accumulation of harmful chemicals at higher trophic levels

What percentage of sun's energy falling on the leaves of green plants is utilised by the plants in the process of photosynthesis and stored as chemical energy of food?
(a) 99 per cent
(b) 10 per cent
(c) 1 per cent
(d) 20 per cent

State whether the following statement is true or false:
A chemical equation can be balanced easily by altering the formula of a reactant or product.

What is wrong with the following chemical equation?

Mg   +   O   →   MgO

Correct and balance it.

What does the symbol (aq) represent in a chemical equation?

Which of the following gets the minimum energy through the food chain in an ecosystem?
(a) carnivore
(b) large carnivore
(c) producer
(d) herbivore