Question Bank — Light: Mirrors and Lenses

NCERT Class 8 Science · Chapter 10 · CBSE Board Pattern

Class 8 Science Chapter 10 Question Bank CBSE Board Pattern

QUESTION BANK

Chapter 10 — Light: Mirrors and Lenses (CBSE Class 8)

Section A — MCQs (10 questions, 1 mark each)

  1. A spherical mirror whose reflecting surface curves inwards is called:
    (a) convex mirror (b) concave mirror (c) plane mirror (d) cylindrical mirror

  2. When an object is placed close to a concave mirror, the image formed is:
    (a) erect and diminished (b) erect and enlarged (c) inverted and diminished (d) inverted and of same size

  3. A convex mirror always forms an image that is:
    (a) erect and enlarged (b) erect and diminished (c) inverted and diminished (d) inverted and enlarged

  4. Assertion (A): Convex mirrors are used as side-view mirrors in vehicles.
    Reason (R): Convex mirrors form erect, diminished images and provide a wider field of view.
    Choose the correct option:
    (i) Both A and R are true and R is the correct explanation of A.
    (ii) Both A and R are true but R is not the correct explanation of A.
    (iii) A is true but R is false.
    (iv) A is false but R is true.

  5. The angle between the incident ray and the normal is called:
    (a) angle of reflection (b) angle of incidence (c) angle of refraction (d) angle of deviation

  6. If a ray of light falls normally on a mirror, the angle of incidence and angle of reflection are:
    (a) 90° each (b) 0° each (c) 45° each (d) 180° each

  7. Assertion (A): A concave mirror can converge parallel rays of sunlight to a point and burn paper.
    Reason (R): A concave mirror reflects parallel rays so that they meet at one point.
    Choose the correct option:
    (i) Both A and R are true and R is the correct explanation of A.
    (ii) Both A and R are true but R is not the correct explanation of A.
    (iii) A is true but R is false.
    (iv) A is false but R is true.

  8. A lens thicker at the middle than at the edges is:
    (a) concave lens (b) convex lens (c) cylindrical lens (d) plane glass

  9. When an object is viewed through a concave lens, the image is always:
    (a) erect and enlarged (b) erect and diminished (c) inverted and diminished (d) inverted and enlarged

  10. Multiple parallel rays falling on a convex mirror after reflection:
    (a) converge (b) diverge (c) remain parallel (d) become perpendicular to the mirror

Section B — Very Short Answer (6 questions, 2 marks each)

  1. Define a spherical mirror. Name the two types of spherical mirrors.
  2. State any two uses of concave mirrors.
  3. What is the difference between the reflecting surface of a concave mirror and a convex mirror?
  4. Write the two laws of reflection.
  5. How does a convex lens affect a beam of parallel rays?
  6. Why is a water drop on a glass surface able to act like a lens?

Section C — Short Answer (5 questions, 3 marks each)

  1. Describe what happens to the image formed by a concave mirror when the object is moved away from the mirror (from very close to far).
  2. Draw a neat labelled ray diagram (on paper) showing an incident ray, reflected ray and normal on a plane mirror. Mark the angle of incidence and angle of reflection.
  3. Differentiate between the image formed by a convex mirror and a concave mirror when the object is placed at a large distance from each.
  4. Explain why a dentist uses a concave mirror while examining teeth.
  5. How will the image of an object change when viewed through a convex lens if the object is moved from a position close to the lens to a position far from the lens?

Section D — Long Answer (3 questions, 5 marks each)

  1. Draw a labelled diagram of a concave mirror showing the reflecting surface, pole, centre of curvature and principal axis (use standard symbols). Explain with the help of the diagram how a concave mirror converges parallel rays of light.
  2. Describe an activity (with labelled diagram) to show that a concave mirror can be used to burn a piece of paper by concentrating sunlight. State the safety precautions to be taken.
  3. Compare the nature of images formed by a convex lens and a concave lens when an object is placed behind them at different distances. Support your answer with observations from activities mentioned in the chapter.

Section E — Case/Source-Based (2 questions, 4 marks each)

25. Meena visited a science centre and saw her image enlarged in one curved mirror and diminished in another. The guide told her these were spherical mirrors.
(a) Which mirror made her face appear large when she stood close?
(b) Which mirror always gives an erect but smaller image?
(c) Name one everyday use of each of these mirrors.
(d) Why do side-view mirrors of vehicles carry the warning “Objects in mirror are closer than they appear”?

26. In a school experiment, students used a convex lens and a concave lens to view printed text. They observed that the text appeared bigger through one lens and smaller through the other.
(a) Which lens made the text appear bigger when held close?
(b) Which lens always makes the object look smaller?
(c) Name the type of lens used in a magnifying glass.
(d) Give one real-life application of each type of lens.

Section F — HOTS and Application (4 questions, 3 marks each)

  1. Predict-and-justify: What would happen to the image in a concave mirror if the object is moved from a position very close to the mirror to a position beyond the centre of curvature? Justify your answer.
  2. In an experiment, parallel rays falling on Mirror X converge after reflection while those falling on Mirror Y diverge. Analyse the observation and identify the two mirrors. Give reason.
  3. A shopkeeper wants to keep an eye on a large area of his store to prevent theft. Which type of mirror should he install and why? Apply the properties of the mirror to justify your choice.
  4. Compare the following two situations and justify which outcome differs and why: (i) an object placed behind a convex lens at a small distance, (ii) the same object placed behind a concave lens at the same distance.
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Section A

  1. (b) 2. (b) 3. (b) 4. (i) 5. (b) 6. (b) 7. (i) 8. (b) 9. (b) 10. (b)

Section B

  1. Spherical mirror – reflecting surface is part of a sphere (1); concave & convex (1).
  2. Any two uses (torch reflector, dentist mirror, headlights) – 1 mark each.
  3. Concave curves inwards, convex curves outwards (2).
  4. i = r (1); incident ray, normal & reflected ray lie in same plane (1).
  5. Converges / brings rays together (2).
  6. Curved surface of water drop acts as convex lens (2).

Section C

  1. Close → erect & enlarged; farther → inverted, size decreases (3 points).
  2. Correct diagram with labels + angles marked (3).
  3. Convex: erect, diminished; Concave: inverted, diminished (3).
  4. Enlarged erect image when held close to teeth (3).
  5. Close → erect enlarged; far → inverted, size changes (3).

Section D

  1. Labelled diagram (pole, centre of curvature, principal axis, reflecting surface) + explanation of convergence (5).
  2. Activity description + diagram of mirror focusing sun rays on paper + safety note (5).
  3. Detailed comparison of image nature for both lenses at different distances (5).

Section E

  1. (a) Concave (1) (b) Convex (1) (c) One use each (1) (d) Wider field of view but image diminished (1).
  2. (a) Convex lens (1) (b) Concave lens (1) (c) Convex (1) (d) One application each (1).

Section F

  1. Image changes from erect enlarged → inverted diminished (reasoning chain with distance).
  2. Mirror X = concave (converges), Mirror Y = convex (diverges) – property based reasoning.
  3. Convex mirror – always erect, diminished + wider field of view.
  4. Convex lens gives enlarged erect image; concave lens gives diminished erect image – difference due to converging vs diverging action.
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All questions are answerable from the NCERT chapter text. Reviewed by GFIS faculty.