Class 10 Science (NCERT)

1. The light-sensitive screen at the back of the human eye where an image is formed is called the:

• A. Cornea
• B. Iris
• C. Retina
• D. Pupil

2. What type of image is formed on the retina of the human eye?

• A. Virtual and erect
• B. Real and inverted
• C. Virtual and inverted
• D. Real and erect

3. The part of the eye that controls the size of the pupil and gives color to the eye is the:

• A. Cornea
• B. Ciliary muscle
• C. Iris
• D. Sclera

4. The least distance of distinct vision for a young adult with normal vision is approximately:

• A. 25 m
• B. 2.5 cm
• C. 25 cm
• D. 2.5 m

5. The far point of a normal human eye is at:

• A. 25 cm
• B. 100 cm
• C. Infinity
• D. 1 kilometer

6. The ability of the eye lens to adjust its focal length is called:

• A. Myopia
• B. Accommodation
• C. Adaptation
• D. Refraction

7. A person suffering from myopia (near-sightedness) cannot see distant objects clearly because the image is formed:

• A. Behind the retina
• B. On the retina
• C. In front of the retina
• D. On the blind spot

8. Myopia (short-sightedness) can be corrected by using spectacles with a suitable:

• A. Convex lens
• B. Concave lens
• C. Bifocal lens
• D. Cylindrical lens

9. Hypermetropia (far-sightedness) is corrected using a lens of which type?

• A. Concave lens
• B. Convex lens
• C. Bifocal lens
• D. Cylindrical lens

10. The defect of vision arising due to aging, where the ciliary muscles weaken and the eye lens loses flexibility, is called:

• A. Myopia
• B. Cataract
• C. Presbyopia
• D. Astigmatism

11. A person requiring a lens of power -2.0 D for vision correction suffers from:

• A. Hypermetropia
• B. Myopia
• C. Presbyopia
• D. Astigmatism

12. The splitting of white light into its component seven colors when passing through a glass prism is called:

• A. Refraction
• B. Reflection
• C. Dispersion
• D. Scattering

13. Which color of white light deviates (bends) the most when passing through a glass prism?

• A. Red
• B. Green
• C. Yellow
• D. Violet

14. Which color of white light bends the least when passing through a glass prism?

• A. Red
• B. Violet
• C. Blue
• D. Orange

15. A rainbow is a natural spectrum appearing in the sky after rain. It is produced by:

• A. Reflection of sunlight by clouds
• B. Dispersion of sunlight by tiny water droplets
• C. Total absorption of light by water vapor
• D. Atmospheric pressure changes

16. The twinkling of stars in the night sky is due to:

• A. Internal reflection inside stars
• B. Atmospheric refraction of starlight
• C. Dispersion of light by clouds
• D. Fluctuations in the light emitted by stars

17. Planets do not twinkle like stars primarily because they:

• A. Are point-sized sources of light
• B. Are closer to Earth and act as extended sources of light
• C. Do not emit light
• D. Are covered by thick atmosphere

18. Advanced sunrise and delayed sunset occur due to:

• A. Scattering of light
• B. Dispersion of sunlight
• C. Atmospheric refraction
• D. Total internal reflection

19. The blue color of the clear sky is caused by:

• A. Dispersion of light by dust
• B. Scattering of light by fine atmospheric particles
• C. Refraction of light in the upper atmosphere
• D. Reflection of sunlight from the ocean

20. According to Rayleigh's law, the intensity of scattered light is inversely proportional to which power of wavelength (λ)?

• A. λ^2
• B. λ^3
• C. λ^4
• D. λ

21. To an astronaut in space (where there is no atmosphere), the sky appears:

• A. Blue
• B. White
• C. Dark / Black
• D. Red

22. The phenomenon of scattering of light by colloidal particles in a medium, making the path of light visible, is known as:

• A. Raman effect
• B. Tyndall effect
• C. Doppler effect
• D. Photoelectric effect

23. Danger signal lights are red in color because red light is:

• A. Scattered the most by fog and smoke
• B. Scattered the least by fog and smoke
• C. Absorbed completely by the atmosphere
• D. Most harmful to human eyes

24. The sun appears reddish at sunrise and sunset because:

• A. Red light is scattered away, leaving blue light
• B. Most blue and shorter wavelength light is scattered away during the long path through atmosphere
• C. The temperature of the sun decreases at sunrise and sunset
• D. The atmosphere absorbs red light

25. The milky cloudy condition of the eye lens in old age that leads to vision loss is called:

• A. Glaucoma
• B. Presbyopia
• C. Cataract
• D. Trachoma

26. Ciliary muscles contract to make the eye lens thicker. This increases the lens curvature and:

• A. Increases focal length to see distant objects
• B. Decreases focal length to see nearby objects
• C. Eliminates color blindness
• D. Decreases the refractive index of cornea

27. Which sensory cells on the retina are responsible for vision in dim light?

• A. Cone cells
• B. Rod cells
• C. Optic nerves
• D. Ciliary cells

28. The focal length of a spectacle lens required by a person having a near point at 100 cm (corrected to 25 cm) is:

• A. +33.3 cm
• B. +25 cm
• C. -33.3 cm
• D. +50 cm

29. When white light passes through two identical inverted glass prisms placed side by side, the emergent beam is:

• A. Dispersed into seven colors
• B. Monochromatic red light
• C. Recombined white light
• D. Completely absorbed

30. At noon, the sun appears white because:

• A. All colors are scattered equally
• B. Light travels a shorter distance through the atmosphere and minimal scattering occurs
• C. Blue color is absorbed by the atmosphere
• D. Red light is scattered the most