Chapter 10: The Human Eye and the Colourful World — Online MCQ Test
SCIENCE · CLASS 10th · Karnataka State Board
Practice Chapter 10: The Human Eye and the Colourful World with a free chapter-wise online MCQ test.
This chapter covers: Human eye Retina Iris Pupil Cornea Myopia Hypermetropia Cataract Atmospheric refraction Rainbow Dispersion.
AI-generated questions from basic to board-exam level, with instant results and explanations.
Chapter 10: The Human Eye and the Colourful World — Important Questions & Answers
The image formed on the retina of the human eye is:
- A. Real and inverted
- B. Virtual and erect
- C. Real and erect
- D. Virtual and inverted
Answer: A. Real and inverted
The eye lens forms a real and inverted image on the retina. The brain interprets this image as erect.
The eye lens forms a real and inverted image on the retina. The brain interprets this image as erect.
Which part of the eye controls the size of the pupil?
- A. Retina
- B. Iris
- C. Cornea
- D. Optic nerve
Answer: B. Iris
The iris is a muscular diaphragm that controls the size of the pupil. This regulates the amount of light entering the eye.
The iris is a muscular diaphragm that controls the size of the pupil. This regulates the amount of light entering the eye.
Most of the refraction of light entering the human eye occurs at the:
- A. Retina
- B. Iris
- C. Cornea
- D. Optic nerve
Answer: C. Cornea
The cornea is the transparent bulged surface of the eye where most of the refraction of incoming light takes place. The eye lens only provides finer adjustment.
The cornea is the transparent bulged surface of the eye where most of the refraction of incoming light takes place. The eye lens only provides finer adjustment.
The least distance of distinct vision for a normal adult human eye is about:
- A. 10 cm
- B. 25 cm
- C. 50 cm
- D. 100 cm
Answer: B. 25 cm
For a normal adult eye, the least distance of distinct vision is about 25 cm. Objects closer than this cannot be seen clearly without strain.
For a normal adult eye, the least distance of distinct vision is about 25 cm. Objects closer than this cannot be seen clearly without strain.
When we enter bright sunlight, the pupil of the eye becomes smaller because:
- A. The retina changes its shape
- B. The iris contracts the pupil to reduce light entry
- C. The cornea becomes opaque
- D. The eye lens stops working
Answer: B. The iris contracts the pupil to reduce light entry
In bright light, the iris reduces the size of the pupil. This prevents too much light from entering the eye.
In bright light, the iris reduces the size of the pupil. This prevents too much light from entering the eye.
A student can read a book clearly but cannot see the blackboard clearly. Which defect is most likely present?
- A. Hypermetropia
- B. Myopia
- C. Cataract only
- D. Colour blindness
Answer: B. Myopia
The student can see nearby objects but not distant objects, which is a sign of myopia. In this defect, distant images are formed in front of the retina.
The student can see nearby objects but not distant objects, which is a sign of myopia. In this defect, distant images are formed in front of the retina.
In myopia, a concave lens is used because it:
- A. Converges the rays before they enter the eye
- B. Diverges the rays so that the image forms on the retina
- C. Blocks excess light from entering the eye
- D. Increases the size of the pupil
Answer: B. Diverges the rays so that the image forms on the retina
In myopia, distant images are formed in front of the retina. A concave lens diverges incoming rays so that the eye lens focuses them on the retina.
In myopia, distant images are formed in front of the retina. A concave lens diverges incoming rays so that the eye lens focuses them on the retina.
A person suffering from both myopia and presbyopia generally uses bifocal lenses. Which arrangement is commonly used?
- A. Upper part convex, lower part concave
- B. Upper part concave, lower part convex
- C. Both parts plane glass
- D. Both parts concave only
Answer: B. Upper part concave, lower part convex
In bifocal lenses, the upper part is usually concave for distant vision and the lower part is convex for reading. This helps correct both myopia and near-vision difficulty.
In bifocal lenses, the upper part is usually concave for distant vision and the lower part is convex for reading. This helps correct both myopia and near-vision difficulty.
A myopic eye has a far point of 50 cm. What lens should be used to correct vision for distant objects?
- A. Concave lens of power -2.0 D
- B. Convex lens of power +2.0 D
- C. Concave lens of power -0.5 D
- D. Convex lens of power +0.5 D
Answer: A. Concave lens of power -2.0 D
For a distant object, the correcting lens must form a virtual image at the far point, 50 cm from the eye. Thus f = -0.50 m and P = -2.0 D.
For a distant object, the correcting lens must form a virtual image at the far point, 50 cm from the eye. Thus f = -0.50 m and P = -2.0 D.
A hypermetropic person has a near point at 1 m. What is the approximate power of the lens required to read a book kept at 25 cm?
- A. +1.0 D
- B. +2.0 D
- C. +3.0 D
- D. -3.0 D
Answer: C. +3.0 D
The lens should form a virtual image at the person's near point, 1 m, for an object at 25 cm. Using 1/f = 1/v - 1/u gives f about 0.33 m, so P is about +3.0 D.
The lens should form a virtual image at the person's near point, 1 m, for an object at 25 cm. Using 1/f = 1/v - 1/u gives f about 0.33 m, so P is about +3.0 D.