Following questions consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Q.1. Assertion(A) : White light is dispersed into its seven-colour components by a prism.
Reason (R) : Different colours of light bend through different angles with respect to the incident ray as they pass through a prism.
Answer
(a)Q.2. Assertion(A) : The phenomenon of scattering of light by the colloidal particles gives rise to Tyndall effect.
Reason (R): The colour of the scattered light depends on the size of the scattering particles.
Answer
(b)Q.3. Assertion(A): A normal human eye can clearly see all the objects beyond certain minimum distance.
Reason (R) : The human eye has capacity of adjusting the focal length of eye lens.
Answer
(a)Q.4. Assertion(A) : A rainbow is sometimes seen in the sky in rainy season only when observer’s back is towards the Sun.
Reason (R) : Internal reflection in the water droplets cause dispersion and the final rays are in backward direction.
Answer
(a)Q.5. Assertion (A) : Myopia is the defect of the eye in which only nearer objects are seen by the eye.
Reason (R) : The eye ball is elongated.
Answer
(a)Q.6. Assertion(A): Hypermetropia is the defect of the eye in which only farther objects are seen.
Reason (R) : Hypermetropia is corrected by using converging lens.
Answer
(b)Q.7. Assertion(A) : Danger signals are made of red colour.
Reason (R) : Velocity of red light in air is maximum, so signals are visible even in dark.
Answer
(c)Q.8. Assertion(A): The sky looks dark and black instead of blue in outer space.
Reason (R) : No atmosphere containing air in the outer space to scatter sunlight.
Answer
(a)Q.9. Assertion (A): The stars twinkle, while the planets do not.
Reason (R) : The stars are much bigger in size than the planets.
Answer
(b)Q.10. Assertion(A): The Sun appears flattened at sunrise and sunset.
Reason (R) : The apparent flattering of the Sun’s disc at sunrise and sunset is due to atmospheric refraction.
Answer
(a)Q.11. Assertion (A) : Blue colour of sky appears due to scattering of blue colour.
Reason (R) : Blue light has longer wavelength.
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