Q1:
Question for Assertion & Reason Type Questions: The Human Eye and the Colourful World
Try yourself:Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
Assertion (A): Eye lens has the ability to focus clearly on the retina by adjusting its focal length.
Reason (R): This phenomenon is known as the power of accommodation.
Explanation
The ability of the eye lens to focus clearly on the retina by adjusting its focal length is known as the power of accommodation.
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Q2:
Question for Assertion & Reason Type Questions: The Human Eye and the Colourful World
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion (A): Concave lens is used to correct myopia or short- sightedness.
Reason (R): A concave lens of suitable focal length diverges the parallel rays from the distant objects as if they are coming from the far point of the myopic eye. This helps the eye lens to form a clear image at the retina.
Explanation
A concave lens of suitable focal length diverges the parallel rays from the distant objects as if they are coming from the far point of the myopic eye. This helps the eye lens to form a clear image at the retina. So, a concave lens is used to correct myopia or short- sightedness.
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Q3:
Question for Assertion & Reason Type Questions: The Human Eye and the Colourful World
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion (A): A white light on passing through prism splits into its component colours as such that the red light emerges nearest to the base of the prism.
Reason (R): Wavelength of red light is more than other component colours and hence, red light deviates least.
Explanation
Dispersion takes place because the refractive index of medium for different wavelengths (colours) is different. The refractive index is inversely proportional to l Since lred is more than other colours wavelength. So, deviation is least for red and it appears farthest from the base of the prism.
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Q4:
Question for Assertion & Reason Type Questions: The Human Eye and the Colourful World
Try yourself: Directions: In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:Assertion (A): In the case of a rainbow, light at the inner surface of the water drop gets internally reflected.
Reason (R): The angle between the refracted ray and normal to the drop surface is greater than the critical angle.
Explanation
The rainbow is formed when light at the inner surface of the water drop gets internally reflected. If the angle between the refracted ray and normal to the drop surface is greater than the critical angle.
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Q5:
Question for Assertion & Reason Type Questions: The Human Eye and the Colourful World
Try yourself: Direction: In the Following Questions, A Statement of Assertion (A) Is Followed by A Statement of Reason (R). Mark The Correct Choice As:Assertion : Hypermetropia is the defect of the eye in which only farther objects are seen.
Reason : Hypermetropia is corrected by using converging lenses.
Explanation
Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
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Q6:
Question for Assertion & Reason Type Questions: The Human Eye and the Colourful World
Try yourself: Direction: In the Following Questions, A Statement of Assertion (A) Is Followed by A Statement of Reason (R). Mark The Correct Choice As:Assertion : Myopia is due to the increased converging power of the eye lens.
Reason : Myopia can be corrected by using spectacles made from concave lenses.
Explanation
Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A). In the Myopia eye due to the increased converging power of the eye lens, the image of a far off object is formed in front of the retina. Myopia can be corrected by using spectacles made from concave lenses.
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Q7:
Question for Assertion & Reason Type Questions: The Human Eye and the Colourful World
Try yourself: Direction: In the Following Questions, A Statement of Assertion (A) Is Followed by A Statement of Reason (R). Mark The Correct Choice As:Assertion : Myopia is the defect of the eye in which only nearer objects are seen by the eye.
Reason : The eyeball is elongated.
Explanation
Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A)
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Q8:
Question for Assertion & Reason Type Questions: The Human Eye and the Colourful World
Try yourself: Direction: In the Following Questions, A Statement of Assertion (A) Is Followed by A Statement of Reason (R). Mark The Correct Choice As:Assertion : The stars twinkle while the planet does not.
Reason : The stars are much bigger in size than the planets.
Explanation
Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A). As planets are of larger size than stars and much closer to the earth, planets can be considered as a collection of large number of point sized sources of light. The total variation in the amount of light entering our eye from all these individual point sized sources will average out to zero which nullifies the twinkling effect of each other. Therefore, planets do not twinkle.
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Q9:
Question for Assertion & Reason Type Questions: The Human Eye and the Colourful World
Try yourself: Direction: In the Following Questions, A Statement of Assertion (A) Is Followed by A Statement of Reason (R). Mark The Correct Choice As:Assertion : A normal human eye can clearly see all the objects beyond a certain minimum distance.
Reason : The human eye has the capacity of adjusting the focal length of eye lens.
Explanation
Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
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Q10:
Question for Assertion & Reason Type Questions: The Human Eye and the Colourful World
Try yourself: Direction: In the Following Questions, A Statement of Assertion (A) Is Followed by A Statement of Reason (R). Mark The Correct Choice As:Assertion : Rainbow is an example of the dispersion of sunlight by the water droplets.
Reason : Light of shorter wavelength is scattered much more than light of larger wavelength.
Explanation
Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
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Q11:
Question for Assertion & Reason Type Questions: The Human Eye and the Colourful World
Try yourself: Direction: In the Following Questions, A Statement of Assertion (A) Is Followed by A Statement of Reason (R). Mark The Correct Choice As:Assertion : A normal human eye can clearly see all the objects beyond a certain minimum distance.
Reason : The human eye has the capacity to adjust suitable the focal length of its lens to a certain extent.
Explanation
Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
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Q12:
Question for Assertion & Reason Type Questions: The Human Eye and the Colourful World
Try yourself: Direction: In the Following Questions, A Statement of Assertion (A) Is Followed by A Statement of Reason (R). Mark The Correct Choice As:Assertion : The optical instruments are used to increase the size of the image of the object.
Reason : The optical instruments are used increase the visual angle.
Explanation
Assertion (A) is false but reason (R) is true.
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Q13:
Question for Assertion & Reason Type Questions: The Human Eye and the Colourful World
Try yourself: Direction: In the Following Questions, A Statement of Assertion (A) Is Followed by A Statement of Reason (R). Mark The Correct Choice As:Assertion : The optical instruments are used to increase the size of the image of the object.
Reason : The optical instruments are used to increase the visual angle.
Explanation
Assertion (A) is false but reason (R) is true. Optical instruments do not increase the size of the image of the object. It depends upon the distance between the object and objective lens.
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Q14:
Question for Assertion & Reason Type Questions: The Human Eye and the Colourful World
Try yourself: Direction: In the Following Questions, A Statement of Assertion (A) Is Followed by A Statement of Reason (R). Mark The Correct Choice As:Assertion : Sunlight reaches us without dispersion in the form of white light and not as its components.
Reason : Dispersion takes place due to variation of refractive index for different wavelength but in vacuum the speed of light is independent of wavelength and hence vacuum is a non-dispersive medium.
Explanation
Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A). In vacuum speed of light is independent of wavelength, Hence, no dispersion takes places in vacuum. Thus, vacuum is a non-dispersive medium in which all colours travel with the same speed.
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Q15:
Question for Assertion & Reason Type Questions: The Human Eye and the Colourful World
Try yourself: Direction: In the Following Questions, A Statement of Assertion (A) Is Followed by A Statement of Reason (R). Mark The Correct Choice As:Assertion : The sky looks dark and black instead of blue in outer space.
Reason : No atmosphere containing air in the outer space to scatter sunlight.
Explanation
Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
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