Introduction

The chapter “Light” is a significant part of the Class 10 Science syllabus. It covers concepts such as reflection, refraction, the behavior of light through lenses and mirrors, and the power of lenses. This blog provides a detailed analysis of important questions from the JKBOSE and CBSE board exams of 2023 and 2024. Each question is paired with a solution, explained step-by-step to ensure clarity.

Why is the Light Chapter Important?

The concepts in this chapter are not only vital for exams but also for real-world applications. Understanding the behavior of light lays the foundation for advanced studies in optics and physics. In board exams, questions from this chapter often include numerical problems, theoretical explanations, and diagram-based queries.

Frequently Asked Questions (2023 & 2024)

Below is a list of the most important questions from the Light chapter that appeared in recent board exams. These are categorized based on the year and include detailed answers.

1. Define the principal focus of a concave mirror. (JKBOSE 2023)

Solution: The principal focus of a concave mirror is the point on its principal axis where light rays parallel to the principal axis converge after reflection.

2. The radius of curvature of a spherical mirror is 24 cm. What is its focal length? (CBSE 2023)

Solution:
The focal length (‘f’) of a spherical mirror is given by: f = R/2.
Given: R = 24 cm
Calculation: f = 24/2 = 12 cm

3. Name the mirror that can give an erect and enlarged image of an object. (JKBOSE 2023)

Solution: A concave mirror can give an erect and enlarged image when the object is placed between the pole and the focus.

4. Why do we prefer a convex mirror as a rear-view mirror in vehicles? (CBSE 2023)

Solution: A convex mirror provides a wider field of view and always forms erect, diminished images, making it ideal for rear-view mirrors.

5. A ray of light traveling in air enters obliquely into water. Does the light ray bend towards or away from the normal? Why? (CBSE 2023)

Solution: The light ray bends towards the normal because water is optically denser than air, and the speed of light decreases in water.

Key Numerical Questions

• Calculate the power of a lens with a focal length of 50 cm. (JKBOSE 2024)
• An object is placed at a distance of 15 cm from a convex mirror of focal length 10 cm. Find the position and nature of the image. (CBSE 2023)
• A concave lens of focal length 20 cm forms an image 15 cm from the lens. How far is the object placed from the lens? (CBSE 2023)

Conclusion

Understanding the Light chapter is essential for scoring well in board exams. This blog aims to simplify complex topics with easy-to-follow solutions. Practice these questions thoroughly to ensure confidence in exams.