Light – Very Short Answer Type Questions

CBSE Class 8 Science – Chapter 16: Light | Very Short Answer Questions

CBSE Class 8 Science – Chapter 16: Light (Very Short Answer Questions)

Class: 8

Subject: Science

Chapter: 16 – Light

These Very Short Answer Questions are designed strictly as per the NCERT Class 8 Science textbook, making them ideal for CBSE Class 8 Board Examination style preparation and quick revision.

CBSE Board Examinations – Topic-wise Very Short Answer Questions

Below is a comprehensive, topic-wise set of 50 Very Short Answer Type Questions from Chapter 16: Light. Answers are kept crisp, clear and concept-based to help students revise fast and score better in CBSE Class 8 examinations.

Topic 1

What Makes Things Visible – Basic Ideas of Light

Q1. What is light?

Ans. Light is a form of energy that enables us to see objects.

Q2. When do we see an object?

Ans. We see an object when light coming from it enters our eyes.

Q3. Why can we not see objects in a completely dark room?

Ans. Because no light is available to reflect from the objects to our eyes.

Q4. What do we call objects that give out their own light?

Ans. Such objects are called luminous objects.

Q5. Give one example of a luminous object other than the Sun.

Ans. An electric bulb (when glowing) is a luminous object.

Q6. What are non-luminous objects?

Ans. Objects that do not emit their own light are non-luminous objects.

Q7. How do non-luminous objects become visible?

Ans. They become visible by reflecting light received from a luminous source.

Topic 2

Rectilinear Propagation of Light and Shadows

Q8. What is meant by rectilinear propagation of light?

Ans. It means that light travels in a straight line.

Q9. Which simple phenomenon proves that light travels in straight lines?

Ans. Formation of sharp shadows proves that light travels in straight lines.

Q10. What is a shadow?

Ans. The dark region formed behind an opaque object when it obstructs light is a shadow.

Q11. Name the three things needed to form a shadow.

Ans. A source of light, an opaque object and a screen.

Q12. Which type of object does not form a complete shadow?

Ans. A transparent object does not form a complete shadow.

Topic 3

Reflection of Light – Basic Terms

Q13. What is reflection of light?

Ans. Bouncing back of light from a surface is called reflection of light.

Q14. What is a mirror?

Ans. A highly polished surface that reflects most of the light is called a mirror.

Q15. Define a plane mirror.

Ans. A flat, smooth reflecting surface is called a plane mirror.

Q16. What is an incident ray?

Ans. The ray of light that falls on a reflecting surface is the incident ray.

Q17. What is a reflected ray?

Ans. The ray of light that bounces back from the reflecting surface is the reflected ray.

Q18. What is the normal at the point of incidence?

Ans. The line drawn perpendicular to the mirror at the point of incidence is the normal.

Q19. Define angle of incidence.

Ans. The angle between the incident ray and the normal is the angle of incidence.

Q20. Define angle of reflection.

Ans. The angle between the reflected ray and the normal is the angle of reflection.

Topic 4

Laws of Reflection and Plane Mirror Image

Q21. State the first law of reflection.

Ans. The incident ray, reflected ray and the normal all lie in the same plane.

Q22. State the second law of reflection.

Ans. The angle of reflection is always equal to the angle of incidence (∠r = ∠i).

Q23. What type of image is formed by a plane mirror: real or virtual?

Ans. A plane mirror forms a virtual image.

Q24. Is the image formed by a plane mirror erect or inverted?

Ans. The image formed by a plane mirror is erect (upright).

Q25. How does the size of the image in a plane mirror compare with the object?

Ans. The image is of the same size as the object.

Q26. How far behind the mirror is the image formed by a plane mirror?

Ans. It is as far behind the mirror as the object is in front of it.

Q27. What is lateral inversion?

Ans. The interchange of left and right sides in a mirror image is called lateral inversion.

Q28. Why is “AMBULANCE” written in reverse on the vehicle?

Ans. So that drivers ahead see it correctly in their rear-view mirrors due to lateral inversion.

Q29. Name one daily use of a plane mirror.

Ans. Dressing mirrors at home are plane mirrors.

Q30. Can the image in a plane mirror be obtained on a screen? Why?

Ans. No, because the image is virtual and not formed by actual meeting of light rays.

Topic 5

Regular and Diffused Reflection

Q31. What is regular reflection?

Ans. Reflection from a smooth surface where parallel rays remain parallel is regular reflection.

Q32. Give one example of a surface that produces regular reflection.

Ans. A plane mirror produces regular reflection.

Q33. What is diffused (irregular) reflection?

Ans. Reflection from a rough surface where rays scatter in many directions is diffused reflection.

Q34. Give an example of a surface that causes diffused reflection.

Ans. A wall or sheet of paper causes diffused reflection.

Q35. Do the laws of reflection hold for diffused reflection?

Ans. Yes, the laws of reflection hold at each point on the uneven surface.

Topic 6

Multiple Reflection, Kaleidoscope and Periscope

Q36. What is multiple reflection?

Ans. Successive reflection of light from two or more mirrors is multiple reflection.

Q37. What happens to the number of images when the angle between two mirrors decreases?

Ans. The number of images increases when the angle decreases.

Q38. Name the device that uses multiple reflections to produce beautiful patterns.

Ans. A kaleidoscope uses multiple reflections to produce patterns.

Q39. How many mirrors are generally used in a simple kaleidoscope?

Ans. Usually three plane mirrors are used.

Q40. Name the device that helps us see objects that are not directly in our line of sight.

Ans. A periscope helps us see objects not in the direct line of sight.

Q41. Where is a periscope commonly used?

Ans. It is used in submarines and by soldiers in trenches.

Q42. How many plane mirrors are used in a simple periscope?

Ans. Two plane mirrors are used in a simple periscope.

Q43. At what angle are the mirrors placed inside a simple periscope?

Ans. The mirrors are placed at 45° to the horizontal.

Topic 7

Sunlight, Colours and Dispersion

Q44. Is sunlight really white or coloured?

Ans. Sunlight appears white but is actually made of many colours.

Q45. What is a spectrum?

Ans. The band of different colours formed when white light splits is called a spectrum.

Q46. Name the seven colours of the sunlight spectrum in order.

Ans. Violet, Indigo, Blue, Green, Yellow, Orange, Red (VIBGYOR).

Q47. What is dispersion of light?

Ans. Splitting of white light into its component colours is dispersion of light.

Q48. Name a transparent object that can produce dispersion of white light.

Ans. A glass prism can produce dispersion of white light.

Q49. Which natural phenomenon shows dispersion of sunlight in the sky?

Ans. A rainbow shows dispersion of sunlight in nature.

Topic 8

Human Eye, Eye Care and Braille System

Q50. Which sense organ helps us to see?

Ans. The human eye helps us to see.

Q51. What is the function of the iris in the eye?

Ans. The iris controls the size of the pupil and hence the amount of light entering the eye.

Q52. What is the pupil?

Ans. The pupil is the small opening in the iris through which light enters the eye.

Q53. Which part of the eye forms the image?

Ans. The lens of the eye forms the image on the retina.

Q54. Name the light-sensitive layer of the eye.

Ans. The retina is the light-sensitive layer of the eye.

Q55. How can reading in dim light affect our eyes?

Ans. It strains the eyes and may cause headache or vision problems.

Q56. What is the Braille system?

Ans. Braille is a system of raised dots used by visually impaired persons for reading and writing.

Q57. Who developed the Braille system?

Ans. The Braille system was developed by Louis Braille.

Q58. How should we protect our eyes from strong sunlight?

Ans. By using proper sunglasses or a sunshade/umbrella and avoiding looking directly at the Sun.

Q59. What should you do if you get persistent eye pain or blurred vision?

Ans. Consult an eye specialist (ophthalmologist) immediately.

Conclusion

This topic-wise set of Very Short Answer Questions for Chapter 16 – Light covers important terms, definitions and facts from the NCERT textbook. Regular practice of these questions will strengthen your fundamentals and help you perform better in CBSE Class 8 Science examinations.