List of top Science Questions

Assertion (A): Human female has a perfect pair of sex chromosomes.
Reason (R): Sex chromosome contributed by the human male in the zygote decides the sex of a child.
A cross between two tall pea plants resulted in offspring having a few dwarf plants. The gene-combination of the parental plants must be
In an experiment to study independent inheritance of two separate traits: shape and colour of seeds, the ratio of the different combinations in F2 progeny would be
two statements are given — one labelled as Assertion (A) and the other labelled as Reason (R). Select the correct answer to these questions from the codes (A), (B), (C) and (D) as given below.
Assertion (A): Chromosomes inherited from the parents decide the sex of a child.
Reason (R): Y chromosome in a male child is inherited from the father.
Assertion (A): Sex of the children will be determined by what they inherit from their mother. Reason (R): Women have XX sex chromosomes.
At what distance from a convex lens should an object be placed to get an image of the same size as that of the object on a screen ?
Assertion (A): Red light signals are used to stop the vehicles on the road.
Reason (R): Red coloured light is scattered the most so as to be visible from a large distance.
The phenomena of light involved in the formation of a rainbow in the sky are
Assertion (A): Offsprings produced by asexual reproduction are genetically similar to the parents.
Reason (R): Asexual reproduction involves a single parent.
A ray of light is incident on a plane mirror at an angle of incidence of 15°. The deviation in the ray produced by the mirror is:
For an object, a convex mirror always forms an image which is:
Assertion (A): The rainbow is a natural spectrum of sunlight in the sky.
Reason (R) : Rainbow is formed in the sky when the sun is overhead and water droplets are also present in air.
Which of the following statement (s) is (are) true about human heart?
(a) Right atrium receives oxygenated blood from lungs through pulmonary artery.
(b) Left atrium transfers oxygenated blood to left ventricle which sends it to various parts of the body.
(c) Right atrium receives deoxygenated blood from different parts of the body through vena cava.
(d) Left atrium transfers oxygenated blood to aorta which sends it to different parts of the body.
The part of a seed that stores food, the future root, and the future shoot respectively are:
The pH of an aqueous solution of a salt is 9. The types of acid and base from which this salt is formed are:
A colourless gas G is produced when egg-shells are treated with a solution S. The gas G turns lime water milky. S and G respectively are:
Select a pair of natural indicator from the following :
A chemical compound used in glass, soap and paper industries is
An aqueous solution of sodium chloride is prepared in distilled water. The pH of this solution is:
When 2 mL of sodium hydroxide solution is added to a few pieces of granulated zinc in a test tube and then warmed, the reaction that occurs can be written in the form of a balanced chemical equation as:
Select from the following a decomposition reaction in which the source of energy for decomposition is light:
Assertion (A) : Hydrogen gas is not evolved when zinc reacts with nitric acid.
Reason (R) : Nitric acid oxidises the hydrogen gas produced to water and itself gets reduced.
Solid Calcium oxide reacts vigorously with water to form Calcium hydroxide accompanied by the liberation of heat. From the information given above it may be concluded that this reaction
Select from the following a process in which a combination reaction is involved:
To balance the chemical equation, the values of the coefficients x, y, z, and t must be: Zn(NO₃)₂ → ZnO + NO₂ + O₂