With reference to the human eye, consider the following statements: 1. The cornea gives the eye its distinctive colour. 2. The pupil appears dark because no light is reflected from it. 3. In bright light, the iris contracts the pupil to allow less light in. Which of the statements given above is/are correct?

The correct option is (c). Explanation The human eye functions as a natural optical instrument. It comprises a lens system (cornea and crystalline lens) that focuses light onto the retina, while the iris acts as a variable aperture to control the intensity of light entering the eye. - Statement 1 is Incorrect: The iris is the pigmented, muscular diaphragm located behind the cornea. It is the iris that contains melanin and gives the eye its distinctive colour (e.g., blue, brown, or green). The cornea is a transparent, convex outer layer responsible for the initial refraction of light. - Statement 2 is Correct: The pupil is the central aperture within the iris. It appears black because the light entering through it is absorbed by the internal tissues of the eye (specifically the retina and choroid) and is not reflected back out through the opening. - Statement 3 is Correct: The iris regulates the amount of light entering the eye by adjusting the diameter of the pupil. In bright light, the circular muscles of the iris contract, causing the pupil to constrict (become smaller). This reduces the amount of light entering the eye to protect the retina. Key Takeaway: The iris determines eye colour and controls the pupil size to regulate light intensity. The pupil appears black due to the absorption of light, and the cornea acts as the transparent window for light entry and refraction.

With reference to the human eye, consider… - NCERT Class 8 Science MCQ

NCERT Class 8 Science — Chapter 4: Light

mcqmedium

With reference to the human eye, consider the following statements:

The cornea gives the eye its distinctive colour.
The pupil appears dark because no light is reflected from it.
In bright light, the iris contracts the pupil to allow less light in.

Which of the statements given above is/are correct?

NCERT textbook question

From NCERT Science - class 8 · Page 172

Options

A1 and 2 only
B2 only
C2 and 3 only
D1, 2 and 3

Did you get this right?

Solution

The correct option is (c).

Explanation

The human eye functions as a natural optical instrument. It comprises a lens system (cornea and crystalline lens) that focuses light onto the retina, while the iris acts as a variable aperture to control the intensity of light entering the eye.

Statement 1 is Incorrect: The iris is the pigmented, muscular diaphragm located behind the cornea. It is the iris that contains melanin and gives the eye its distinctive colour (e.g., blue, brown, or green). The cornea is a transparent, convex outer layer responsible for the initial refraction of light.
Statement 2 is Correct: The pupil is the central aperture within the iris. It appears black because the light entering through it is absorbed by the internal tissues of the eye (specifically the retina and choroid) and is not reflected back out through the opening.
Statement 3 is Correct: The iris regulates the amount of light entering the eye by adjusting the diameter of the pupil. In bright light, the circular muscles of the iris contract, causing the pupil to constrict (become smaller). This reduces the amount of light entering the eye to protect the retina.

Key Takeaway: The iris determines eye colour and controls the pupil size to regulate light intensity. The pupil appears black due to the absorption of light, and the cornea acts as the transparent window for light entry and refraction.

Your note

More from Chapter 4: Light

With reference to the Periscope, consider the following statements: 1. It works on the principle of multiple reflections. 2. It uses two plane mirrors arranged at right angles to each other. 3. It allows viewing of objects that are not directly in the line of sight. Which of the statements given above are correct?

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With reference to image formation by a plane mirror, consider the following statements: 1. The image formed cannot be obtained on a screen. 2. The image appears at a greater distance behind the mirror than the object is in front. 3. The image undergoes lateral inversion. Which of the statements given above are correct?

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Consider the following statements about the image formed by a plane mirror: 1. It is inverted vertically. 2. It is of the same size as the object. 3. It appears to be at the same distance behind the mirror as the object is in front. Which of the statements given above is/are correct?

easy

In the context of the reflection of light, what does the term 'angle of incidence' refer to?

easy

With reference to the eye's ability to see, consider the following statements: 1. A normal eye can clearly see distant objects as well as objects nearby. 2. The minimum distance for distinct vision is constant at 50 cm for all ages. 3. In old age, eyesight may become foggy due to the eye lens becoming cloudy. Which of the statements given above is/are correct?

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