Question 1

The human eye's ability to focus on objects at varying distances by altering the focal length of its lens is known as:

Accepted Answer

Answer: accommodation. The ability of the eye lens to adjust its focal length to see both near and distant objects clearly is defined as the power of accommodation.

Question 2

In the human eye, the image of an object is formed on the:

Accepted Answer

Answer: retina. The retina is the light-sensitive screen at the back of the eye where the eye lens forms a real and inverted image of the object.

Question 3

For a young adult with normal vision, the minimum distance for clear vision is approximately:

Accepted Answer

Answer: 25 cm. The least distance of distinct vision, also known as the near point, for a normal human eye is conventionally taken as 25 cm.

Question 4

The focal length of the eye lens is adjusted by the action of the:

Accepted Answer

Answer: ciliary muscles. The ciliary muscles are responsible for changing the shape and curvature of the eye lens, which in turn alters its focal length.

Question 5

At which part of the human eye does the majority of the refraction of incoming light rays occur?

Accepted Answer

Answer: Outer surface of Cornea. The greatest refraction of light entering the eye happens at the outer surface of the cornea. The crystalline lens primarily provides finer adjustments to the focal length.

Question 6

Which of the following statements correctly describes the curvature of the human eye lens?

Accepted Answer

Answer: increases or decreases as the case may be.. The curvature of the eye lens is controlled by the ciliary muscles, which can increase or decrease it to focus on objects at different distances.

Question 7

Identify the part of the human eye that controls the amount of light entering it.

Accepted Answer

Answer: Pupil. The pupil is the aperture that allows light to enter the eye. The iris controls the size of the pupil, thereby regulating the amount of light that passes through. In this context, the pupil is the direct regulator of light entry.

Question 8

On which light-sensitive screen does the lens system of the human eye project an image?

Accepted Answer

Answer: Retina. The retina acts as the light-sensitive screen at the back of the eye where the lens system forms an image.

Question 9

Evaluate the following statements concerning the human eye and determine which are correct:
(A) The diameter of the human eyeball is approximately 2.3 cm.
(B) The iris is a dark, muscular diaphragm that controls the size of the pupil.
(C) The majority of light refraction upon entering the eye occurs at the crystalline lens.
(D) Focusing on objects at different distances is achieved by adjusting the distance between the crystalline lens and the retina.

Accepted Answer

Answer: Statements (A) and (B). Statement (A) is a known anatomical fact. Statement (B) correctly describes the function of the iris. Statement (C) is incorrect because most refraction occurs at the cornea. Statement (D) is incorrect as the eye adjusts its focal length via the ciliary muscles, not the lens-retina distance.

Class 10 Science: The Human Eye — Practice Questions with Answers

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