What is Light Exercises in Class 8 Science NCERT?

The Class 8 Science NCERT Chapter 10 — Light: Mirrors and Lenses exercise section tests students on all the key concepts covered in the chapter, including NCERT exercises, mirror questions, lens questions, eye defect questions, competency-based questions. It includes multiple-choice questions (MCQs…

What does the NCERT Class 8 Science Light: Mirrors and Lenses exercise section cover?

The Class 8 Science NCERT Chapter 10 u2014 Light: Mirrors and Lenses exercise section tests students on all the key concepts covered in the chapter, including NCERT exercises, mirror questions, lens questions, eye defect questions, competency-based questions. It includes multiple-choice questions (MCQs), assertion-reason questions, short-answer questions, long-answer questions, and competency-based questions that align with the NCERT Curiosity textbook. Working through these exercises helps Class 8 students reinforce their conceptual understanding, prepare for classroom assessments, and build exam readiness for CBSE school tests. Each question links back to a specific section of the chapter so students can revise the theory alongside the practice.

How should Class 8 students approach the Light: Mirrors and Lenses exercises?

Class 8 students should approach the Light: Mirrors and Lenses exercises by first revising the main theory and definitions from each part of the chapter, especially around NCERT exercises and mirror questions. Start with the MCQs and assertion-reason questions to quickly test recall, then attempt the short-answer questions that need a one or two-line explanation, and finally tackle the long-answer and competency-based questions that require applying concepts to new situations. Write neat diagrams wherever the question involves a process, cycle, or setup, and always use NCERT-style vocabulary in your answers to match CBSE marking schemes.

Are these Light: Mirrors and Lenses questions competency-based as per NEP 2020?

Yes, the Light: Mirrors and Lenses exercise set follows the NEP 2020 competency-based education (CBE) framework used by CBSE and NCERT for Class 8 Science. Instead of only asking students to recall definitions, many questions are scenario-based and require applying the concept to real-life situations, analysing data, or evaluating claims. This matches Bloom's Taxonomy levels L3 (Apply), L4 (Analyse), and L5 (Evaluate), going beyond rote learning. Students practising these questions build the higher-order thinking skills that modern CBSE school exams increasingly assess, and also prepare well for competitive foundation tests in later years.

Which NCERT Curiosity sections are tested in Chapter 10 exercises?

The Chapter 10 u2014 Light: Mirrors and Lenses exercise set systematically tests every major section of the NCERT Curiosity Class 8 Science textbook for this chapter. Topics covered include NCERT exercises, mirror questions, lens questions, eye defect questions, competency-based questions. Every in-text question, activity-linked question, and end-of-chapter question from the Curiosity book is represented, so students can be confident that completing this exercise set gives them full coverage of the NCERT syllabus. Teachers also frequently pick questions from these sections for school unit tests and half-yearly exams, making thorough practice essential for strong performance.

How do assertion-reason questions work in this Class 8 Science chapter?

Assertion-reason questions in the Class 8 Science Light: Mirrors and Lenses exercise set present two statements u2014 an Assertion (A) and a Reason (R) u2014 and ask students to judge whether each is true and whether R correctly explains A. Students pick from four standard options: both true with R explaining A, both true but R not explaining A, A true and R false, or A false. This format tests whether Class 8 learners genuinely understand the cause-and-effect relationships behind NCERT exercises, not just surface facts. Mastering this format is valuable because CBSE Class 10 board exams use the same pattern.

What is the best revision strategy before attempting these exercises?

The best revision strategy before attempting Light: Mirrors and Lenses exercises is to read through all theory parts of NCERT Curiosity Chapter 10 once, write down the key terms such as NCERT exercises, mirror questions, lens questions, eye defect questions, competency-based questions in your own words, and then re-do all activities mentally to understand the underlying concept. Next, make a one-page mind map linking the main ideas. Only then attempt the exercise questions u2014 first without looking back, then self-correcting. This active-recall approach builds much stronger long-term memory than repeatedly re-reading the textbook, and is widely recommended by CBSE teachers for Class 8 Science preparation.

What does the NCERT Class 8 Science Light: Mirrors and Lenses exercise section cover?

The Class 8 Science NCERT Chapter 10 — Light: Mirrors and Lenses exercise section tests students on all the key concepts covered in the chapter, including NCERT exercises, mirror questions, lens questions, eye defect questions, competency-based questions. It includes multiple-choice questions (MCQs), assertion-reason questions, short-answer questions, long-answer questions, and competency-based questions that align with the NCERT Curiosity textbook. Working through these exercises helps Class 8 students reinforce their conceptual understanding, prepare for classroom assessments, and build exam readiness for CBSE school tests. Each question links back to a specific section of the chapter so students can revise the theory alongside the practice.

How should Class 8 students approach the Light: Mirrors and Lenses exercises?

Class 8 students should approach the Light: Mirrors and Lenses exercises by first revising the main theory and definitions from each part of the chapter, especially around NCERT exercises and mirror questions. Start with the MCQs and assertion-reason questions to quickly test recall, then attempt the short-answer questions that need a one or two-line explanation, and finally tackle the long-answer and competency-based questions that require applying concepts to new situations. Write neat diagrams wherever the question involves a process, cycle, or setup, and always use NCERT-style vocabulary in your answers to match CBSE marking schemes.

Are these Light: Mirrors and Lenses questions competency-based as per NEP 2020?

Yes, the Light: Mirrors and Lenses exercise set follows the NEP 2020 competency-based education (CBE) framework used by CBSE and NCERT for Class 8 Science. Instead of only asking students to recall definitions, many questions are scenario-based and require applying the concept to real-life situations, analysing data, or evaluating claims. This matches Bloom's Taxonomy levels L3 (Apply), L4 (Analyse), and L5 (Evaluate), going beyond rote learning. Students practising these questions build the higher-order thinking skills that modern CBSE school exams increasingly assess, and also prepare well for competitive foundation tests in later years.

Which NCERT Curiosity sections are tested in Chapter 10 exercises?

The Chapter 10 — Light: Mirrors and Lenses exercise set systematically tests every major section of the NCERT Curiosity Class 8 Science textbook for this chapter. Topics covered include NCERT exercises, mirror questions, lens questions, eye defect questions, competency-based questions. Every in-text question, activity-linked question, and end-of-chapter question from the Curiosity book is represented, so students can be confident that completing this exercise set gives them full coverage of the NCERT syllabus. Teachers also frequently pick questions from these sections for school unit tests and half-yearly exams, making thorough practice essential for strong performance.

How do assertion-reason questions work in this Class 8 Science chapter?

Assertion-reason questions in the Class 8 Science Light: Mirrors and Lenses exercise set present two statements — an Assertion (A) and a Reason (R) — and ask students to judge whether each is true and whether R correctly explains A. Students pick from four standard options: both true with R explaining A, both true but R not explaining A, A true and R false, or A false. This format tests whether Class 8 learners genuinely understand the cause-and-effect relationships behind NCERT exercises, not just surface facts. Mastering this format is valuable because CBSE Class 10 board exams use the same pattern.

What is the best revision strategy before attempting these exercises?

The best revision strategy before attempting Light: Mirrors and Lenses exercises is to read through all theory parts of NCERT Curiosity Chapter 10 once, write down the key terms such as NCERT exercises, mirror questions, lens questions, eye defect questions, competency-based questions in your own words, and then re-do all activities mentally to understand the underlying concept. Next, make a one-page mind map linking the main ideas. Only then attempt the exercise questions — first without looking back, then self-correcting. This active-recall approach builds much stronger long-term memory than repeatedly re-reading the textbook, and is widely recommended by CBSE teachers for Class 8 Science preparation.

TOPIC 38 OF 50

Light Mirrors Lenses — Exercises

🎓 Class 8 Science CBSE Theory Ch 10 — Force and Pressure ⏱ ~20 min

🌐 Language: [gtranslate]

🧠 AI-Powered MCQ Assessment ▲

This MCQ module is based on: Light Mirrors Lenses — Exercises

No. of Questions:

Difficulty Level:

Myaischool Lt Science Assessment ▲

[myaischool_lt_science_assessment grade_level="class_8" science_domain="physics" difficulty="basic"]

📚 Chapter Summary

Plane Mirror

Image is virtual, erect, same size, laterally inverted. Behind the mirror at the same distance as the object.

Concave Mirror

Converging. Image may be real/inverted (object beyond F) or virtual/erect/enlarged (object within F).

Convex Mirror

Diverging. Always forms a virtual, erect, diminished image. Wide field of view.

Concave Mirror Uses

Shaving mirror, dentist's mirror, torch, headlight, solar cooker, reflecting telescope.

Convex Mirror Uses

Vehicle side mirrors, hill-road safety, shop surveillance, ATMs. Note the "closer than they appear" warning.

Convex Lens

Thicker in the middle, converging. Used in cameras, projectors, microscopes, telescopes, magnifying glasses, eye.

Concave Lens

Thinner in the middle, diverging. Always gives a virtual, erect, smaller image. Used in myopia spectacles.

Human Eye

Cornea → pupil (iris) → eye lens (convex) → retina → optic nerve → brain. Accommodation focuses near/far objects.

Myopia

Short-sightedness. Image forms before retina. Corrected by a concave lens.

Hypermetropia

Long-sightedness. Image would form behind retina. Corrected by a convex lens.

Presbyopia

Age-related stiffening of the lens. Often needs bifocal glasses.

Astigmatism

Uneven cornea curvature. Corrected by cylindrical lenses.

🔑 Key Terms

ReflectionBouncing of light from a surface.

RefractionBending of light as it passes through a new medium.

Pole (P)Centre point of a curved mirror's surface.

Centre of Curvature (C)Centre of the sphere the mirror is cut from.

Focus (F)Point where parallel rays meet or appear to meet.

Focal length (f)Distance from pole to focus.

Real imageImage formed by rays that actually meet; can be shown on a screen.

Virtual imageImage formed by rays that only appear to meet; cannot be caught on a screen.

Lateral inversionLeft-right swap in a mirror image.

Concave mirrorCurved mirror reflecting from the inside of a sphere; converging.

Convex mirrorCurved mirror reflecting from the outside; diverging.

Convex lensThicker in the middle; converges light.

Concave lensThinner in the middle; diverges light.

AccommodationPower of the eye lens to change its focal length.

Persistence of visionRetina holds image for ~1/16 s after object is gone.

MyopiaShort-sightedness; corrected by concave lens.

HypermetropiaLong-sightedness; corrected by convex lens.

PresbyopiaAge-related weakening of lens focusing.

📝 Exercises

Q1. Fill in the blanks:
(a) A plane mirror forms a ______ image.
(b) A concave mirror is also called a ______ mirror.
(c) A convex lens is ______ in the middle.
(d) Myopia is corrected by a ______ lens.

(a) virtual (b) converging (c) thicker (d) concave

Q2. State True (T) or False (F):
(a) A convex mirror always makes the image larger than the object.
(b) A concave mirror can form both real and virtual images.
(c) The image on the retina is erect.
(d) The iris controls the amount of light entering the eye.

(a) F — convex mirrors always give diminished images. (b) T. (c) F — the image on the retina is inverted; the brain interprets it. (d) T — the iris adjusts the pupil's opening.

Q3. Differentiate between a real image and a virtual image. Give one example of each.

A real image is formed when reflected or refracted rays actually meet; it can be caught on a screen and is always inverted (example: image of a distant tree on a screen using a convex lens). A virtual image is formed when the rays only appear to meet after being extended backwards; it cannot be caught on a screen and is usually erect (example: your face in a plane mirror).

Q4. Why is a convex mirror used as a rear-view mirror in vehicles?

A convex mirror always forms an erect, diminished image. Because the image is smaller, a wider area of the road behind gets fitted into the same mirror, giving the driver a large field of view. This is more important for safety than exact size — though drivers must remember the warning "objects in mirror are closer than they appear".

Q5. With a labelled ray diagram, show how an image is formed by a concave mirror when an object is placed between its pole and focus.

Draw a concave mirror with its principal axis, mark pole (P), focus (F) and centre of curvature (C). Place an erect object between P and F. From the top of the object, draw (i) a ray parallel to the principal axis that reflects through F and (ii) a ray aimed at C that returns along itself. The two reflected rays diverge, so extend them backwards — they meet behind the mirror. The image is virtual, erect and enlarged. This is the shaving-mirror case.

Q6. Explain why the word "AMBULANCE" is written in mirror-reversed form on the front of an ambulance vehicle.

A plane mirror inverts left and right (lateral inversion). The rear-view mirror of a car in front sees a reflection of whatever is behind it. If "AMBULANCE" were written normally on the vehicle, drivers ahead would read it reversed in their rear-view mirrors. By printing the word reversed on the ambulance, the rear-view mirror reverses it once more, so drivers see it the right way round and give way quickly.

Q7. Compare a concave mirror and a convex lens with respect to: (i) shape of reflecting/refracting surface, (ii) nature of image for a distant object, (iii) one common use.

(i) Concave mirror — inner surface of a sphere, silvered on the outer side; Convex lens — transparent, thicker in the middle, bulging on both sides. (ii) Both form a real, inverted, diminished image of a distant object. (iii) Concave mirror → solar cooker / headlamp reflector; Convex lens → camera / magnifying glass.

Q8. Name the parts of the human eye through which light travels before it reaches the retina.

Light passes through the cornea, then through the aqueous humour, through the opening of the pupil (controlled by the iris), into the flexible eye lens, and finally through the clear jelly-like vitreous humour before falling on the retina.

Q9. Neha cannot read the blackboard from the last bench of her classroom but reads her book easily. What defect is she likely to have, and what corrective lens does she need?

Neha has myopia (short-sightedness). Light from the distant blackboard is being focused before it reaches her retina, making it blurry. She needs spectacles containing a suitable concave (diverging) lens, which will push the image back on to the retina.

Q10. A 60-year-old woman needs different glasses for reading and for watching television. Explain the defect and the type of spectacles likely prescribed.

With age, the eye lens hardens and loses its ability to change focal length — a defect called presbyopia. Some older people also develop myopia for far vision along with presbyopia for near vision. She would be prescribed bifocal spectacles: the upper portion contains a concave lens (for distant vision such as watching TV) while the lower portion contains a convex lens (for reading).

Q11. An object is placed at the focus of a concave mirror. Where is the image formed and what is used in?

When an object is placed exactly at the focus F, the reflected rays emerge parallel to the principal axis. The image is therefore formed at infinity, highly enlarged and inverted. This principle is used in search lights, car headlamps and torches — a small bulb placed at the focus of a concave reflector sends out a strong, nearly parallel beam that travels far into the dark.

Q12. Describe Activity 10.2 (concentrating sunlight with a concave mirror) and explain the physics behind the bright spot.

Hold a small concave mirror in sunlight and place a piece of dark paper a few centimetres in front of its reflecting side. Move the paper until a very small, very bright spot appears on it. The distance between the paper and the mirror at this moment is the focal length (f) of the mirror. Since parallel rays from the Sun converge at F, all the Sun's energy striking the mirror gets concentrated at that tiny spot. The paper can become hot enough to smoke or catch fire — exactly how solar cookers and solar furnaces function. Never focus sunlight on skin or eyes.

AI Tutor

Science Class 8 — Curiosity

Ready

Hi! 👋 I'm Gaura, your AI Tutor for Light Mirrors Lenses — Exercises. Take your time studying the lesson — whenever you have a doubt, just ask me! I'm here to help.