English Medium Class 9 - CBSE Question Bank Solutions

______ have guard cells.

Give reasons for

We get a crunchy and granular feeling when we chew pear fruit.

Give reasons for

Branches of a tree move and bend freely in high wind velocity.

List the characteristics of cork. How are they formed? Mention their role.

Suppose a ball of mass m is thrown vertically upward with an initial speed v, its speed decreases continuously till it becomes zero. Thereafter, the ball begins to fall downward and attains the speed v again before striking the ground. It implies that the magnitude of the initial and final momentums of the ball are the same. Yet, it is not an example of conservation of momentum. Explain why?

Which of the above two graphs (a) and (b) (Fig.12.3) representing the human voice is likely to be the male voice? Give a reason for your answer.

A girl is sitting in the middle of a park of dimension 12 m × 12 m. On the left side of it, there is a building adjoining the park and on the right side of the park, there is a road adjoining the park. A sound is produced on the road by a cracker. Is it possible for the girl to hear the echo of this sound? Explain your answer.

For hearing the loudest ticking sound heard by the ear, find the angle x in Fig.12.4.

If you live in an overcrowded and poorly ventilated house, it is possible that you may suffer from which of the following diseases

Which disease is not transmitted by mosquitoes?

Which separation technique will you apply for the separation of the following?

Different pigments from an extract of flower petals.

How many atoms are present in a PO₄³⁻ ion?

What are polyatomic ions? Give examples.

Calculate the number of aluminium ions present in 0.051 g of aluminium oxide.

(Hint: The mass of an ion is the same as that of an atom of the same element. Atomic mass of Al = 27 u)

Write the distribution of electrons in carbon and sodium atoms?

If K and L shells of an atom are full, then what would be the total number of electrons in the atom?

Summarize the rules for writing of distribution of electrons in various shells for the first eighteen elements.

Na⁺ has completely filled K and L shells. Explain.

Which one of the following is a correct electronic configuration of sodium?

Name the tissue responsible for movement in our body.