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Important Questions: CBSE Class 8 Science Chapter 13 Light

Chapter 13 Light in CBSE Class 8 Science introduces students to reflection and its laws, multiple reflections, dispersion of white light and the structure of the human eye with vision defects. Understanding these concepts through rigorous question practice is essential because Light contributes 4–6 marks in the final exam. This page groups exam-style important questions by marks weightage and provides model answers so students can self-assess and refine their preparation.

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Key takeaways

✓Chapter 13 Light carries approximately 4–6 marks in the final CBSE Class 8 Science exam, spread over MCQs, short answers and one long answer or case-based question.
✓Reflection and its two laws form the backbone of one-mark and two-mark questions; diagram-based queries on plane mirrors and kaleidoscopes are frequent.
✓Dispersion of white light through a glass prism is tested via three-mark diagram questions and conceptual fill-in-the-blanks.
✓The human eye, defects like myopia and hypermetropia, and their corrections using concave or convex lenses appear in five-mark structured questions.
✓Common mistakes include confusing angle of incidence with angle of reflection, misstating the order of colours in VIBGYOR, and interchanging corrective lenses for vision defects.
✓Practising 15–18 past-year-style questions with model answers builds speed, accuracy and confidence for board and internal assessments.
✓CBSETUTOR.ai's 24×7 AI tutor lets students photo-upload any Light question for instant step-by-step solutions at a flat ₹999/month across Classes 6–12, with a three-day free trial.

Chapter Overview and Marks Weightage in CBSE Class 8 Science Exam

Chapter 13 Light falls under the Physics strand of the CBSE Class 8 Science syllabus. The NCERT textbook divides the chapter into four major topics: reflection and laws of reflection, multiple reflections in plane mirrors, dispersion of white light through a prism, and the human eye including common vision defects like myopia and hypermetropia. In the annual exam, Light typically attracts 4–6 marks distributed across one or two MCQs worth one mark each, a couple of two-mark VSAs, at least one three-mark diagram-based question on dispersion or kaleidoscope, and one five-mark structured question on the human eye or a case-based scenario. Internal periodic tests and competency-based assessments also draw heavily on ray diagrams, labelling exercises and application-level reasoning. Mastering the terminology — angle of incidence, angle of reflection, spectrum, retina, cornea, ciliary muscles — is non-negotiable because CBSE examiners award marks for precise NCERT language. The chapter builds foundational optics skills that recur in Classes 10 and 12, so thorough practice now pays long-term dividends.

Reflection and laws – approximately 1–2 marks via MCQ or one VSA.
Multiple reflections and kaleidoscope – 2–3 marks through diagram labelling or construction description.
Dispersion through prism – 3 marks for a ray diagram with VIBGYOR sequence.
Human eye structure and vision defects – 4–5 marks in a structured long answer or case study.
Total chapter weightage: 4–6 marks out of 80 in the annual CBSE Class 8 Science exam.

1-Mark Questions: Multiple Choice and Very Short Answer

One-mark questions test recall of definitions, laws and terminology. CBSE typically sets two to three MCQs or fill-in-the-blank statements from this chapter. Expect questions on the laws of reflection, the number of images formed by parallel mirrors, the cause of dispersion, parts of the eye or the type of lens used to correct a specific defect. Answers must be crisp—often a single word, a short phrase or a correctly ticked option. Speed matters; students should finish these in under thirty seconds each. Pay attention to exact NCERT wording: for instance, stating that the incident ray, reflected ray and normal lie in the same plane is essential for the second law of reflection. Below are five representative one-mark questions with model answers drawn from past patterns and NCERT exercises.

2-Mark Questions: Short Answer Type

Two-mark questions demand brief explanations, comparisons or descriptions in two to three sentences. They often ask students to state both laws of reflection together, explain why a kaleidoscope produces multiple images, list any two parts of the human eye with functions, or compare the corrective lenses for myopia and hypermetropia. Examiners look for clarity and correct terminology; vague statements like 'light bends' instead of 'light refracts' cost marks. Diagrams are rarely required in two-mark answers, but if you sketch a simple ray to support your explanation, label it neatly. Aim to finish each question in about two minutes, using bullet sub-points if the answer has two distinct parts. Below are four typical two-mark questions with concise model answers that match CBSE mark schemes.

3-Mark Questions: Diagram-Based and Application Questions

Three-mark questions typically require a labelled ray diagram, a detailed explanation or an application scenario. Popular themes include drawing the path of white light through a glass prism to show dispersion with the sequence VIBGYOR clearly labelled, sketching the structure of the human eye with at least five parts identified, or explaining the construction and working of a periscope using two plane mirrors. Examiners allocate one mark for the diagram, one for correct labels and one for the accompanying description or reasoning. Neatness counts: use a sharp pencil, a ruler for rays and arrows to show direction. Avoid sketching freehand curves where straight lines are needed. Write explanations in three to four sentences, linking cause and effect explicitly. Reserve about four minutes per three-mark question during the exam. Below are three worked examples that reflect actual CBSE question styles.

5-Mark Questions: Long Answer and Case-Based Questions

Five-mark questions are the chapter's crown jewels. They test synthesis, application and the ability to link multiple concepts. Expect structured questions such as 'Describe the structure and functioning of the human eye. Explain myopia, its cause and correction with a ray diagram' or a case study presenting a real-life scenario—for example, a student unable to see the blackboard clearly from the back row—and asking you to identify the defect, explain the cause and suggest the corrective lens with reasoning. CBSE awards one mark for each distinct point: definition, cause, symptom, diagram and correction. Write in well-organized paragraphs or numbered sub-answers. Include a labelled ray diagram wherever asked; even if the question does not explicitly mention a diagram, adding one for myopia or hypermetropia often fetches an extra mark for presentation. Allocate seven to eight minutes per five-mark question. Below are two comprehensive examples with model answers broken into mark-worthy components.

How CBSE Frames Questions from Chapter 13 Light

Understanding the CBSE question-setting pattern helps you anticipate what examiners will ask and how they will ask it. The board pulls content directly from NCERT in-text questions, end-of-chapter exercises and activity boxes. For reflection and laws, expect definitional one-mark MCQs and two-mark 'state the laws' questions. Multiple reflections are tested through kaleidoscope construction or periscope working, often in three-mark diagram format. Dispersion questions almost always demand a labelled prism diagram with VIBGYOR sequence; sometimes a follow-up asks why the sky is blue or sunsets are red, linking to scattering concepts hinted at in the chapter. Human eye questions are favourite five-markers: examiners combine structure labelling with a defect, its cause and correction. Case-based questions introduced recently present a real-world situation—someone struggling to thread a needle or read road signs—and you must identify the defect and suggest the lens. Competency-based questions may show two ray diagrams and ask which represents myopia. Diagram neatness, accurate terminology and logical sequencing of points maximize your marks. Practising previous years' board papers and NCERT exemplar problems is the single best way to internalize these patterns.

Laws of reflection: one-mark fill-in-the-blank or MCQ; two-mark 'state both laws'.
Kaleidoscope or periscope: three-mark construction and working with diagram.
Dispersion: three-mark prism diagram with VIBGYOR labelling and brief explanation of cause.
Human eye structure: two-mark or three-mark labelling exercise.
Myopia or hypermetropia: five-mark structured question—definition, cause, correction, ray diagram.
Case-based: scenario description followed by part questions worth five marks total.
Competency-based: identify defect from given ray diagrams or match lens types to defects.

Common Mistakes Students Make and How to Avoid Them

Every year, CBSE evaluators note recurring errors in Light answers that cost students easy marks. One frequent mistake is confusing the angle of incidence with the angle of reflection; remember both are measured from the normal, not from the mirror surface, and are always equal. Another pitfall is stating the VIBGYOR sequence incorrectly—writing ROYGBIV (the mnemonic some students learn) instead of the actual order Violet to Red as light exits the prism. In human eye diagrams, students often mislabel the retina as the lens or forget to draw the optic nerve, losing the label mark. When explaining vision defects, mixing up the corrective lenses is common: writing 'concave lens for hypermetropia' is wrong and costs both the correction mark and the reasoning mark. In ray diagrams, failing to use a ruler results in wobbly lines that examiners struggle to interpret; always draw straight incident and reflected rays with arrowheads. Omitting labels or using vague terms like 'colored part' instead of 'iris' also invites mark deductions. During dispersion questions, students sometimes write that the prism adds colours to white light, rather than explaining that white light already contains seven colours which refract differently. Finally, many skip units or omit the word 'lens' when stating corrections, writing just 'concave' without 'lens'. A careful review of your answer script before submission catches most of these errors.

Confusing angle measurement: always measure angles from the normal, not the mirror surface.
Wrong VIBGYOR order: the correct sequence emerging from the prism is Violet, Indigo, Blue, Green, Yellow, Orange, Red.
Mislabelling eye parts: know the exact NCERT terms—cornea, lens, retina, iris, pupil, optic nerve, ciliary muscles.
Swapping corrective lenses: concave for myopia, convex for hypermetropia; do not reverse them.
Freehand diagrams: use a ruler and pencil for all rays, normals and mirror edges.
Vague language: write 'concave lens' or 'convex lens', not just 'concave' or 'lens'.
Believing the prism creates colours: white light already contains seven colours; the prism only separates them by refraction.

Additional 3-Mark and 5-Mark Practice Questions with Model Answers

To deepen your mastery, here are three more important questions that blend diagram skills, reasoning and application. These mirror the difficulty and format seen in board exams and school internals. Work through them under timed conditions, then compare your answers with the models provided. Focus on clarity, correct sequence and precise terminology. If your answer differs slightly but covers the same key points, that is acceptable; CBSE mark schemes allow for varied phrasing as long as the science is accurate. Regular practice of such questions builds muscle memory for exam day, so aim to solve at least ten to fifteen similar problems from NCERT exemplar, previous years' papers and reference guides before your final assessment.

How CBSETUTOR.ai Helps You Master Chapter 13 Light Questions

Solving important questions is most effective when you get instant, personalized feedback. CBSETUTOR.ai offers a 24×7 AI tutor that allows Class 8 students to photo-upload any question from Chapter 13 Light—whether it is a tricky ray diagram, a dispersion numericals or a case study on vision defects—and receive step-by-step solutions within seconds. The platform is designed specifically for the CBSE curriculum, so explanations use NCERT terminology and align with board mark schemes. Parents appreciate the transparency: one flat fee of ₹999 per month covers all subjects and all classes from 6 to 24, with no hidden charges or per-question fees. Students can practice unlimited questions, clarify doubts at any hour and review solutions as many times as needed, building confidence and accuracy before exams. A three-day free trial lets families test the feature set risk-free. Beyond question solving, CBSETUTOR.ai provides curated question banks, chapter-wise tests and progress analytics so students and parents can track improvement over time. For busy families in metro cities juggling school, tuitions and extracurriculars, having an always-available AI tutor removes the stress of last-minute doubt clearing and ensures no concept is left misunderstood.

Photo-upload any Light question and get instant step-by-step solutions aligned to CBSE marking schemes.
Unlimited practice across all Class 8 Science chapters at ₹999/month—one price for Classes 6 to 12.
Three-day free trial with no credit card required; cancel anytime.
NCERT-grounded explanations using exact chapter terminology for reflection, dispersion and human eye.
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Ideal for students in coaching-heavy cities and Tier-2 towns where personalized attention is hard to find.

Study Tips and Revision Strategy for Chapter 13 Light

Start your preparation by reading the NCERT textbook chapter thoroughly, highlighting definitions, laws and the VIBGYOR sequence. Make a one-page summary sheet listing the two laws of reflection, the parts of the eye with functions, the two main vision defects with causes and corrections, and the dispersion diagram. Practice drawing the prism diagram and the human eye diagram at least five times each until you can reproduce them neatly in under two minutes. Solve all in-text questions and end-of-chapter exercises; these are the primary source pool for board questions. Next, work through the important questions on this page under timed conditions—allocate one minute per mark as a rough guide. Review your answers against the model solutions, noting any terminology gaps or diagram errors. Create flashcards for terms like cornea, retina, myopia, hypermetropia, dispersion and spectrum; quiz yourself daily. A week before the exam, attempt a full-length mock test covering all chapters, then focus your remaining revision on areas where you lost marks. On exam day, read each question twice, underline keywords like 'draw', 'state', 'explain' and allocate your time proportionally. If a five-mark question asks for a diagram, spend one minute on the diagram, one on labelling and three on the written explanation. Finally, reserve five minutes at the end to review your answer sheet, checking that all diagrams are labelled, all laws are stated in full, and VIBGYOR is in the correct order.

Read NCERT Chapter 13 and underline key definitions, laws and the VIBGYOR sequence.
Draw the prism dispersion diagram and human eye diagram repeatedly until you achieve speed and accuracy.
Solve all NCERT in-text and end-of-chapter questions; they form the core question bank.
Practice the 18 questions on this page under timed conditions, then compare with model answers.
Make flashcards for technical terms and quiz yourself daily.
Attempt a full-length mock test one week before the exam to identify weak topics.
On exam day, read questions carefully, underline action words, draw diagrams with a ruler and reserve time for final review.

Frequently asked questions

How many marks does Chapter 13 Light carry in the CBSE Class 8 Science annual exam?+

Chapter 13 Light typically carries 4–6 marks in the CBSE Class 8 Science annual exam. This includes one or two one-mark MCQs, a couple of two-mark short answers, one three-mark diagram question on dispersion or kaleidoscope, and one five-mark structured question or case study on the human eye or vision defects.

What are the two laws of reflection I must remember for the exam?+

The first law states that the angle of incidence is equal to the angle of reflection. The second law states that the incident ray, the reflected ray and the normal at the point of incidence all lie in the same plane. Both laws are frequently tested in one-mark or two-mark questions.

What is the correct sequence of colours in the spectrum formed by a prism?+

The correct sequence, from bottom to top as light exits the prism, is Violet, Indigo, Blue, Green, Yellow, Orange, Red—remembered by the acronym VIBGYOR. Writing this sequence in reverse or out of order will cost you marks in dispersion questions.

Which lens is used to correct myopia, and which for hypermetropia?+

Myopia (short-sightedness) is corrected using a concave lens, which diverges light rays so the image shifts back onto the retina. Hypermetropia (long-sightedness) is corrected using a convex lens, which converges rays to bring the image forward onto the retina. Do not swap these.

Do I need to draw diagrams in every question on Light?+

Not every question, but diagram-based questions are common and high-value. Three-mark questions on dispersion, kaleidoscope or periscope and five-mark questions on vision defects almost always require labelled ray diagrams. Even if not explicitly asked, adding a neat diagram can earn presentation marks.

What are the most common mistakes students make in Chapter 13 Light answers?+

Common mistakes include measuring angles from the mirror surface instead of the normal, writing the VIBGYOR sequence incorrectly, mislabelling parts of the eye, swapping concave and convex lenses for myopia and hypermetropia, and drawing freehand diagrams without a ruler. Careful review before submission helps catch these errors.

How should I practice important questions for Chapter 13 Light?+

Start by solving all NCERT in-text and end-of-chapter questions. Then work through the 18 questions on this page under timed conditions—one minute per mark. Compare your answers with the model solutions, noting any terminology or diagram gaps. Repeat with NCERT exemplar and previous years' board papers.

Can CBSETUTOR.ai help if I get stuck on a Light diagram question?+

Yes. CBSETUTOR.ai's AI tutor lets you photo-upload any diagram question from Chapter 13 and receive a step-by-step solution with labelled sketches within seconds. The platform is available 24×7 at ₹999/month for all classes 6–12, with a three-day free trial and no per-question fees.

Are case-based questions included in the Class 8 Science exam for Chapter 13?+

Yes. CBSE has introduced competency-based and case-based questions across all classes. For Chapter 13, expect a five-mark case study presenting a real-life vision problem—someone unable to see distant or near objects—and asking you to identify the defect, state the cause, suggest the corrective lens and draw a ray diagram.

What is the best revision strategy one week before the Science exam?+

One week out, consolidate your one-page summary of laws, parts of the eye, defects and corrections. Practice drawing the prism and eye diagrams daily. Solve a full-length mock test covering all chapters, then deep-dive into chapters where you lost marks. Reserve the final day for quick revision of definitions, VIBGYOR sequence and flashcard drills—avoid learning new material.

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