Hello students! Welcome to our new post, where we bring you a collection of Assertion and Reason questions from CBSE Class 10 Science Previous Year Question Papers. These questions have been carefully selected to help you get familiar with the latest exam trends and question patterns. Practicing these Assertion and Reason questions will sharpen your critical thinking and concept clarity. Whether you're revising or preparing for your exams, this post will be a valuable resource. Let's dive in and boost your Science preparation!
Instructions
For the following questions number 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.
(A) Both Assertion (A) and Reason (R)
are true and Reason (R) is the correct explanation of the Assertion (A).
(B) Both Assertion (A) and Reason (R)
are true, but Reason (R) is not the correct explanation of the Assertion (A).
(C) Assertion (A) is true, but Reason
(R) is false.
(D)
Assertion (A) is false, but Reason (R) is true.
1.
Assertion (A): The rate of breathing in aquatic organisms is much faster than in terrestrial organisms.
Reason (R): The amount of oxygen dissolved in water is very high as compared to the amount of oxygen in air.
2.
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.
3.
Assertion (A): Accumulation of harmful chemicals is maximum in the organisms at the highest trophic level of a food chain.
Reason (R): Harmful chemicals are sprayed on the crops to protect them from diseases and pests.
4.
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.
5.
Assertion (A): Metals in the middle of activity series are found in nature as sulphides or carbonates.
Reason (R): The sulphide ores are calcinated whereas carbonate ores are roasted to extract metals from them.
6.
Assertion (A): Human female has a perfect pair of sex chromosome.
Reason (R): Sex chromosome contributed by the human male in the zygote decides the sex of a child.
7.
Assertion (A): The deflection of a compass needle placed near a current carrying wire decreases when the magnitude of an electric current in the wire is increased.
Reason (R): Strength of the magnetic field at a point due to a current carrying conductor increases on increasing the current in the conductor.
8.
Assertion (A): Myopic eye cannot see distant objects distinctly.
Reason (R): For the correction of myopia converging lenses of appropriate power are prescribed by eye-surgeons.
9.
Assertion (A): Oxides of metals show basic characters.
Reason (R): Oxides of metals react with acid to form salt and water.
10.
Assertion (A): In human beings, males have 'XX' sex chromosomes and females have 'XY' sex chromosomes.
Reason (R): Sex of the child is determined at the time of fertilisation when male and female gamete fuse to form a zygote.
11.
Assertion (A): Receptors are usually located in our sense organs and perceive a particular stimulus.
Reason (R): Different sense organs have different receptors for detecting stimuli.
12.
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.
13.
Assertion (A): Magnetic field lines never intersect each other.
Reason (R): If they intersect, then at the point of intersection, the compass needle would point towards two directions, which is not possible.
14.
Assertion (A): Oxygen is essential for all aerobic forms of life.
Reason (R): Free oxygen atoms combine with molecular oxygen to form ozone.
15.
Assertion (A): Most of the plants close their stomata at night.
Reason (R): Closing of stomata helps to conserve water as large amount of water evaporates from the leaves.
16.
Assertion (A): The extraction of metals from their sulphide ores cannot take place without roasting of the ore.
Reason (R): Roasting converts sulphide ores directly into metals.
17.
Assertion (A): Ozone layer protects the surface of the Earth from harmful UV radiations.
Reason (R): Chlorofluorocarbons (CFCs) are responsible for depletion of ozone layer.
18.
Assertion (A): Some vegetable oils are healthy.
Reason (R): Vegetable oils generally have long unsaturated carbon chains.
19.
Assertion (A): Sex of the children will be determined by what they inherit from their mother.
Reason (R): Women have XX sex chromosomes.
20.
Assertion (A): Electrons move from lower potential to higher potential in a conductor.
Reason (R): A dry cell maintains electric potential difference across the ends of a conductor.