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Light Reflection and Refraction Class 10 Important Questions - FREE PDF Download
Vedantu provides important questions for Class 10 Science Chapter 9, "Light: Reflection and Refraction," to help students understand the core concepts of this chapter. Covering key topics like the laws of reflection, refraction of light, image formation by mirrors and lenses, and critical angles, these questions are designed to align with the CBSE exam pattern. By practising these light reflection and refraction class 10 important questions with answers, students can strengthen their understanding and improve their problem-solving skills. Download the FREE PDF of these important questions to revise effectively and excel in your exams.
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Students can strengthen their understanding and confidently approach exam questions by practising these light chapter class 10 important questions, prepared as per the latest Class 10 Science Syllabus.
CBSE Class 10 Science Important Questions - Chapter 9 Light Reflection and Refraction
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The following list of important topics covered under the chapter on Light Reflection and Refraction has been provided for students so that they can take a glance at the major concepts and read them through before diving into the important questions.
Reflection of Light
Spherical Mirrors
Image Formation by Spherical Mirrors
Sign Convention for Spherical Mirrors
Mirror Formula and Magnification
Refraction of Light
Refraction through a Rectangular Glass Slab
Refractive Index
Refraction by Spherical Lenses
Image Formation by Lenses and Their Ray Diagrams
Sign Convention for Spherical Lenses
Lens Formula and Magnification
Power of a Lens
Study Important Questions for Class 10 Science Chapter 9 - Light Reflection and Refraction
Long Answer Questions (5 Marks)
1. A convex lens has a focal length of \[10\] cm. At what distance from the lens should the object be placed so that it forms a real and inverted image $20$ cm. away from the lens? What would be the size of the image formed if the object is $2$ cm high? With the help of a ray, the diagram shows the formation of the image by the lens in this case?
Ans: Given, the focal length of the convex lens,
$\Rightarrow f=+10$ cm
Also, given the image formed is real and inverted with the image distance as $20$ cm.
$\Rightarrow v=+20$ cm
From the lens formula, we have:
$\Rightarrow \dfrac{1}{f}=\dfrac{1}{v}-\dfrac{1}{u}$
$\Rightarrow \dfrac{1}{10}=\dfrac{1}{20}-\dfrac{1}{u}$
$\Rightarrow \dfrac{1}{u}=\dfrac{1}{20}-\dfrac{1}{10}$
$\Rightarrow \dfrac{1}{u}=\dfrac{-1}{20}$
$\Rightarrow u=-20$ cm.
$\therefore $ The object is placed at a distance of $20$ cm.
Magnification is given as,
$\Rightarrow m=-\dfrac{v}{u}$
$\Rightarrow m=-\dfrac{20}{\left( -20 \right)}$
$\Rightarrow m=+1$
Also, magnification is given by, $m=\dfrac{Height\text{ of the image}}{Height\text{ of the object}}$.
$\therefore m=\dfrac{Height\text{ of the image}}{2}$
$\Rightarrow 1=\dfrac{Height\text{ of the image}}{2}$
$\Rightarrow Height\text{ of the image}=2$ cm.
Thus, the image is of the same size as that of the object and it is real and inverted.
The ray diagram representing the formation of the image by the lens in this case is:
It is observed that the image is formed at $2{F_2}$ with the object placed at $2{F_1}$.
2. Draw a ray diagram to show the use of a convex lens for the formation of images having the following characteristics.
a. Real & inverted and diminished
Ans: A ray diagram representing a real & inverted and diminished image is given below.
When the object is kept outside $2{F_1}$ (Centre), we get a real, inverted, and diminished image between ${F_2}$ and $2{F_2}$.
b. Virtual, erect & magnified.
Ans: A ray diagram representing a virtual, erect, and magnified image is given below.
When the object is kept at a distance less than ${F_1}$ (Focus), we get a virtual, erect, and magnified image outside $2{F_1}$ (Centre).
3. A convex lens forms a real and inverted image of a needle at a distance of $50$ cm. from it. Where is the needle placed in front of the convex lens if the image is equal to the size of objects? Also, find the power of the lens.
Ans: Given, the image is real and inverted at a distance of $50$ cm.
$\Rightarrow v=+50$ cm
Also given, Height of image $=$ Height of object
We know, magnification is given as,
$\Rightarrow m=-\dfrac{v}{u}$
Also, magnification is given by, $m=\dfrac{Height\text{ of the image}}{Height\text{ of the object}}$.
$\therefore -\dfrac{v}{u}=\dfrac{Height\text{ of the image}}{Height\text{ of the object}}$
Since, Height of image $=$ Height of object and $v=+50$ cm
$\Rightarrow -\dfrac{50}{u}=1$
$\Rightarrow u=-50$ cm
From the lens formula, we have:
$\Rightarrow \dfrac{1}{f}=\dfrac{1}{v}-\dfrac{1}{u}$
$\Rightarrow \dfrac{1}{f}=\dfrac{1}{50}-\dfrac{1}{-50}$
$\Rightarrow f=25$ cm
$\Rightarrow f=0.25$ m
The power of a lens is given by,
$\Rightarrow P=\dfrac{1}{f}$
$\Rightarrow P=\dfrac{1}{0.25}$ m
$\Rightarrow P=+4$ D
4. One-half of a convex lens is covered with black paper. Will this lens produce a complete image of the object? Verify your answers experimentally. Explain your observations.
Ans: If we cover one-half of a convex lens with black paper it is observed that it produces a complete image of the object.
Representing the given situation with a ray diagram.
Suppose we take a convex lens that is half-covered with black paper. On one side of the lens, we keep a burning candle and a screen on the other side of the lens.
Adjust the position of the burning candle such that its image is formed on the screen placed on the other side of the lens.
We get a full image of the burning candle on the screen.
Thus, from the above observation, we conclude that the formation of an image does not depend on the length of the lens, but the brightness of the image formed on the screen depends since the number of rays passing through the lens gets reduced on covering half the lens with black paper.
5. An object $5$ cm in length is held $25$ cm away from a converging lens of focal length $10$ cm. Draw the ray diagram and find the position, size, and nature of the image formed.
Ans: Given focal length of the lens, $f=+10$ cm.
Object distance from the converging lens is given to be $25$ cm and the height of the object ($ho$) is given to be $5$ cm.
Thus,
$\Rightarrow u=-25$ cm
$\Rightarrow ho=5$ cm
From the lens formula, we have:
$\Rightarrow \dfrac{1}{f}=\dfrac{1}{v}-\dfrac{1}{u}$
$\Rightarrow \dfrac{1}{10}=\dfrac{1}{v}-\dfrac{1}{-25}$
$\Rightarrow \dfrac{1}{v}=\dfrac{1}{25}-\dfrac{1}{10}$
$\Rightarrow v=\dfrac{50}{3}$ cm
$\Rightarrow v=16.7$ cm
Thus, we conclude that the image formed is real and inverted and is formed at a distance of $16.7$ cm on the other side of the lens.
We know, magnification is given as,
$\Rightarrow m=-\dfrac{v}{u}$
Also, magnification is given by, $m=\dfrac{Height\text{ of the image}}{Height\text{ of the object}}=\dfrac{hi}{ho}$.
$\therefore -\dfrac{v}{u}=\dfrac{hi}{ho}$
$\Rightarrow \dfrac{16.7}{-25}=\dfrac{hi}{5}$
$\Rightarrow hi=-\dfrac{10}{3}$ cm
Hence, the image is diminished.
The ray diagram representing the above situation is drawn below.
6. A convex lens of focal length $15$ cm formed an image $10$ cm from the lens. How far is the object placed from the lens? Draw the ray diagram.
Ans: Given focal length of the lens, $f=15$ cm.
Image distance from the converging lens is given to be $10$ cm.
Thus,
$\Rightarrow v=-10$ cm
We observe that the image distance is less than the focal length, hence the image formed would be virtual and erect.
From the lens formula, we have:
$\Rightarrow \dfrac{1}{f}=\dfrac{1}{v}-\dfrac{1}{u}$
$\Rightarrow \dfrac{1}{15}=\dfrac{1}{-10}-\dfrac{1}{u}$
$\Rightarrow \dfrac{1}{u}=-\dfrac{1}{10}-\dfrac{1}{15}$
$\Rightarrow u=-6$ cm
The ray diagram representing the above situation is drawn below.
Light: Reflection and Refraction - Important Questions and Solutions Summary
light rays, mirrors, lenses, prisms, etc., is the advanced version of what you As mentioned earlier, the chapter related to light, reflection, and refraction of have studied in the previous classes. In Class 10, you will have to focus on the theoretical part, as well as, the use of these theories to answer questions.
After you have completed answering the basic questions in the exercise, you might need a question bank to learn more about this chapter. This is where Light Reflection and Refraction Class 10 Important Questions with Answers can be used perfectly. These questions will intellectually challenge your knowledge and foundation of concepts based on this topic. You can answer on your own and check whether you know the right answer or not.
Class 10 Light Reflection and Refraction Important Questions have been developed by the expert teachers to provide a strong idea of how questions are set in the exams. All these questions are developed to define how theoretical concepts are used to solve conceptual problems. You will gain a better insight into the chapters and strengthen your foundation accordingly.
Important Topics of Class 10 Science Chapter 9 Light Reflection and Refraction
Benefits of Learning with Class 10 Science Light Chapter Class 10 Important Questions
Light Chapter Class 10 Important Questions help students understand the core concepts of light, such as reflection, refraction, and image formation, ensuring a strong foundation for further studies.
The light chapter class 10 important questions are aligned with the CBSE exam pattern, allowing students to become familiar with the types of questions that can appear in the exam and building their confidence.
By practising light chapter class 10 important questions, students can develop effective problem-solving techniques and learn how to approach different types of numerical and theoretical questions.
The important questions serve as a great revision tool, helping students recap key concepts and formulas just before the exam.
Solving Light Chapter Class 10 Important Questions regularly enables students to practice managing their time more effectively, which is crucial during the actual exam.
As students work through these light chapter class 10 important questions, they are likely to clear any doubts and misunderstandings related to key topics, which enhances their overall understanding.
Conclusion
The important questions for Class 10 Science Chapter 9, "Light: Reflection and Refraction," provided by Vedantu, offer students a comprehensive way to strengthen their understanding of key concepts like reflection, refraction, and image formation by mirrors and lenses. The light class 10 extra questions, designed in alignment with the CBSE exam pattern, help students practise effectively and clear any doubts related to the chapter. Regular revision and practice using these important questions can significantly build confidence and improve exam performance. Download the FREE PDF from Vedantu for thorough exam preparation.
Important Study Materials for Class 10 Science Chapter 9 Light Reflection and Refraction
Important Questions Chapter-wise Links for Class 10 Science
Related Study Material Links for Class 10 Science
FAQs on CBSE Class 10 Science Important Questions - Chapter 9 Light Reflection and Refraction
1. What are the most important topics to focus on for scoring maximum marks in CBSE Class 10 Science Chapter 9 Light Reflection and Refraction?
For board exams, focus on laws of reflection and refraction, image formation by spherical mirrors and lenses, mirror/lens formulas, sign conventions, ray diagrams, refractive index, and power of a lens. These topics frequently appear in 3- and 5-mark questions.
2. How are important questions from Light Reflection and Refraction typically distributed by marks in board exams?
The questions are usually structured as follows:
- 1-mark: Definitions and direct fact-based concepts
- 2- or 3-mark: Reasoning, drawing ray diagrams, applying formulas for numericals
- 5-mark (Long Answer): Detailed numericals involving formulas, steps, diagrams, and conceptual explanation, or comparative reasoning
3. Why are ray diagrams considered crucial in important questions from this chapter?
Ray diagrams visually show how images are formed by mirrors and lenses. Board questions often assess your ability to draw and label them accurately, as they help explain principles of reflection/refraction, image position, size, and nature.
4. What common mistakes should students avoid when solving important numerical questions in Light Reflection and Refraction?
Key mistakes to avoid:
- Incorrectly applying sign conventions for object/image distances
- Missing unit conversions (cm to m, especially for power calculations)
- Incomplete ray diagrams or missing labels
- Confusing real and virtual image properties
5. How should students approach 5-mark important questions that combine theory and numerical parts?
Structure your answer by:
- Writing relevant formulas with correct units
- Step-by-step calculation showing substitution
- Drawing and accurately labeling associated ray diagrams
- Adding a short explanation or conclusion as required
6. What is typically asked about the sign conventions in board important questions, and why do they matter?
Questions test your ability to remember and apply the sign conventions (New Cartesian Sign Convention) for measuring object and image distances. Using incorrect signs can result in wrong answers in numericals and is a frequent cause of mistakes.
7. In what ways do CBSE board important questions test understanding of the difference between reflection and refraction?
These questions often require comparison in tabular form, application in real-life scenarios, or identification of differences using diagrams. Understanding both mechanisms and being able to distinguish their effects is highly valued.
8. Why do many important questions include scenarios with partially covered lenses or mirrors?
Such questions test conceptual depth—whether you understand that reducing the area of a lens does not affect the completeness of the image, but affects brightness. They often appear as HOTS (Higher Order Thinking Skills) questions.
9. How can practicing board important questions on Light Reflection and Refraction help improve time management during the exam?
Regular practice familiarizes you with question patterns and time needed for numericals, ray diagrams, and explanations, helping you allocate the right time to each section and avoid last-minute rush.
10. What trends are seen in CBSE Class 10 expected questions for Chapter 9 based on previous board exams?
Trends show repeated focus on:
- Application of mirror and lens formulae
- Drawing and interpretation of ray diagrams
- Numerical problems involving magnification, image position, and power of lens
- Comparisons and differences (reflection vs refraction, concave vs convex)
11. What are some conceptual traps in Light Reflection and Refraction that students must watch for in important questions?
Common traps include:
- Confusing the sign convention usage
- Assuming image type incorrectly based on object position
- Omitting physical meaning of calculation steps
12. How do HOTS (Higher Order Thinking Skills) questions in this chapter differ from standard important questions?
HOTS questions go beyond direct application, asking for explanation of non-standard scenarios (e.g., effect of changing medium, half-lens usage, or multi-step reasoning). Prepare by understanding the underlying principles, not just rote solutions.
13. What kind of comparative questions on mirrors and lenses appear in the important questions set?
Comparative board questions may require:
- Differences between concave/convex mirrors or lenses in terms of image formation
- Tabulated comparisons of their uses and properties
- Application-focused reasoning (e.g., why certain mirrors are used in vehicles)
14. Why is it important to understand the calculation of the power of a lens in board important questions?
Calculating the power of a lens demonstrates mastery over lens formula application and unit management. It is a key skill assessed in numericals and necessary for solving complex problems in the CBSE board exam.
15. What strategies can help in identifying which important questions are most likely to be asked in the CBSE 2025-26 board exam for Light Reflection and Refraction?
Strategies include:
- Analyzing previous years’ board papers for high-frequency topics
- Consulting official CBSE marking schemes
- Practicing conceptual and numerically intensive questions with diagrams
- Focusing on recent syllabus and pattern changes
