English Medium Class 10 - CBSE Important Questions for Science

Answer the following question.
In the experimental set up to show that "CO2 is given out during respiration", name the substance taken in the small test tube kept in the conical flask. State its function and the consequence of its use.

What happens at the synapse between two neurons?

Which of the following endocrine gland does not occur as a pair in the human body?

A student was asked to observe and identify the various parts of an embryo of a red kidney bean seed. He identified the parts and listed them as under:

I. Tegmen

II. Testa

III. Cotyledon

IV. Radicle

V. Plumule

The correctly identified parts among these are

(A) I, II and III

(B) II, III and IV

(C) III, IV and V

(D) I, III, IV and V

In the following diagram showing the structure of embryo of a dicot seed, what are the parts marked I, II and III sequentially?

A student has to perform the experiment "To identify the different parts of an embryo of a dicot seed." Select from the following an appropriate group of seeds:

(a) Pea, gram, wheat

(b) Red kidney bean, maize, gram

(c) Maize, wheat, red kidney bean

(d) Red kidney bean, pea, gram

Name and differentiate between the two modes of pollination in flowering plants.

A student identified the various parts of an embryo of a gram seed and listed them as given below :

(I) Testa

(II) Plumule

(III) Radicle

(IV) Cotyledon

(V) Tegmen

Out of these the actual parts of the embryo are :

(A) I, II, III

(B) II, III, IV

(C) III, IV, V

(D) II, IV, V

You are asked by your teacher to study the different parts of an embryo of a gram seed. Given below are the steps to be followed for the experiment:

I. Soak the gram seeds in plain water and keep them overnight.

II. Cut open a soaked seed and observe its different parts.

III. Take some dry gram seeds in a petri dish.

IV. Drain the excess water.

V. Cover the soaked seeds with a wet cotton cloth and leave them for a day.

The correct sequence of these steps is :

(A) III, I, V, IV, II

(B) III, I, II, IV, V

(C) III, IV, V, I, II

(D) III, I, IV, V, II

(a) Identify A, B and C in the given diagram and write their functions.

(b) Mention the role of gamete and zygote in sexually reproducing organisms.

In the figure, the parts marked A, B and C are sequentially:

(A) Plumule, Radicle and Cotyledon

(B) Radicle, Plumule and Cotyledon

(C) Plumule, Cotyledon and Radicle

(D) Radicle, Cotyledon and Plumule

Answer the following question.
How does suitable pollination lead to fertilization?

A student is observing the temporary mount of a leaf peel under a microscope. Draw a labelled diagram of the structure of stomata as seen under the microscope

In flowering plants, the pollen grains are transferred to stigma by pollination but the female germ cells are present in the ovary.
Explain with the help of a labelled diagram (only concerned parts), how the male germ cell reaches the ovary.

Consider the following three flowers namely X, Y and Z. Which flower(s) would develop into a fruit?

Flower X	Flower Y	Flower Z

One half of a convex lens of focal length 10 cm is covered with a black paper. Can such a lens produce an image of a complete object placed at a distance of 30 cm from the lens? Draw a ray diagram to justify your answer. A 4 cm tall object is placed perpendicular to its principal axis of a convex lens of focal length 20 cm. The distance of the object from the lens is 15 cm. Find the nature, position and the size of the image.

A student obtains a sharp image of the distant window (W) of the school laboratory on the screen (S) using the given concave mirror (M) to determine its focal length. Which of the following distances should he measure to get the focal length of the mirror?

A student used a device (X) to obtain/focus the image of a well illuminated distant building on a screen (S) as shown below in the diagram. Select the correct statement about the device (X).

A 4 cm tall object is placed on the principal axis of a convex lens. The distance of the object from the optical centre of the lens is 12 cm and its sharp image is formed at a distance of 24 cm from it on a screen on the other side of the lens. If the object is now moved a little away from the lens, in which way (towards the lens or away from the lens) will he have to move the screen to get a sharp image of the object on it again? How will the magnification of the image be affected?

Explain the following term related to spherical lenses:- optical centre