English Medium इयत्ता १० - CBSE Question Bank Solutions for Science

Write the name and molecular formula of the first member of the homologous series of alkynes.

Why homologous series of carbon compounds are so called? Write chemical formula of two consecutive members of a homologous series and state the part of these compounds that determines their (i) physical properties, and (ii) chemical properties.

Study the different conclusions drawn by students of a class on the basis of observations of preserved/available specimens of plants and animals.

I. Potato and sweet potato are analogous organs in plants.

II. Wings of insects and wings of birds are homologous organs in animals.

III. Wings of insects and wings of bats are analogous organs in animals.

IV. Thorns of citrus and tendrils of cucurbita are analogous organs in plants.

The correct conclusions are:

(A) I, and II

(B) II and IV

(C) I and III

(D) III and IV

Define homologous series of organic compounds. List its two characteristics. Write the name and formula of the first member of the series of alkenes.

Distinguish between homologous organs and analogous organs. In which category would you place wings of a bird and wings of a bat? Justify your answer giving a suitable reason.

Define the principal focus of a concave mirror.

Light enters from air to glass having refractive index 1.50. What is the speed of light in the glass? The speed of light in vacuum is 3 × 10⁸ m s⁻¹.

What is atmospheric reflection? Explain with the help of a labelled diagram that the position of a star as seen by us is not its true position. 

What is haemoglobin? State the consequences of deficiency of haemoglobin in our bodies. 

List four characteristics of the image formed by a concave lens of focal length 20 cm when the object is placed at a distance of 40 cm from its optical centre. 

The size of image of an object by a convex lens of focal length 20 cm is observed to be reduced to  `1/3` rd of its size . Find the distance of the object from the optical centre of the lens . 

List in proper sequence the steps of the experiment for determining the approximate focal length of a given concave mirror by obtaining the image of a distant object.

Choose the correct option from given alternative:
A real image is formed by the light rays after reflection or refraction when they:
(A) actually meet or intersect with each other.
(B) actually converge at a point
(C) appear to meet when they are produced in the backward direction.
(D) appear to diverge from a point.
Which of the above statements are correct?

Write the mathematical expression for Joule’s law of heating.

Compute the heat generated while transferring 96000 coulombs of charge in two hours through a potential difference of 40 V.

The laws of reflection hold true for ______.

Two statements are given - one labeled Assertion (A) and the other labeled Reason (R).
Assertion (A): In a homologous series of alcohols, the formula for the second member is C₂H₅OH and the third member is C₃H₇OH.
Reason (R): The difference between the molecular masses of the two consecutive members of a homologous series is 144.

Write two devices based on the heating effect of electric current.

In a closed circulatory system, blood is completely enclosed within:

You are given water, mustard oil, glycerine and kerosene. In which of these media a ray of light incident obliquely at same angle would bend the most?