CBSE Class 10 Science: Light - Reflection and Refraction | Important Concept-Based Questions

CBSE Class 10 Science: Light — Reflection & Refraction

Important Concept-Based Questions | Notes | Exam Strategy

📘 Introduction

Light plays a vital role in our daily lives and scientific understanding. In the CBSE Class 10 Science syllabus, the chapter on Light: Reflection and Refraction builds a foundation for optical concepts used in higher studies and real-life applications like cameras, mirrors, and lenses. Let’s explore the key concepts, diagrams, and important concept-based questions that make you exam-ready!

⭐ Table of Contents

• Laws of Reflection
• Laws of Refraction
• Spherical Mirrors and Mirror Formula
• Lenses and Refractive Index
• Important Concept-Based Questions
• Exam Tips & Tricks
• Contact & Counselling

🌟 Reflection of Light

Reflection occurs when light bounces off a surface. Two fundamental laws govern this phenomenon:

1. The angle of incidence equals the angle of reflection (∠i = ∠r).
2. The incident ray, reflected ray, and normal all lie in the same plane.

Types of reflection include regular reflection (from smooth surfaces) and diffused reflection (from rough surfaces).

💡 Refraction of Light

When light travels from one medium to another, its speed changes, causing it to bend. This bending is called refraction.

• Snell’s Law: The ratio of sin(i) to sin(r) is constant for a pair of media.
• Formula: n = sin i / sin r
• Refractive Index (n): It shows how much a medium can bend light.

🔍 Spherical Mirrors

Spherical mirrors are part of a sphere and can be:

• Concave Mirror: Converges light and forms real or virtual images.
• Convex Mirror: Diverges light and always forms a virtual, erect, and diminished image.

Mirror Formula: 1/f = 1/v + 1/u

Magnification: m = -v/u

🔬 Lenses and Refraction

Lenses refract light to form images. They are of two main types:

• Convex Lens: Converging lens that can form real or virtual images.
• Concave Lens: Diverging lens that forms virtual and diminished images.

Lens Formula: 1/f = 1/v - 1/u

Refractive Index Formula: n = c/v

📝 Important Concept-Based Questions

Conceptual Questions

1. State the laws of reflection and refraction.
2. Explain why a convex mirror always forms a virtual image.
3. Differentiate between real and virtual images with examples.
4. What is total internal reflection? Give two examples.
5. Why does a pencil appear bent when placed in water?

Numerical Questions

1. An object is placed 20 cm from a convex lens, and the image forms 60 cm away. Find focal length.
2. Light enters glass from air at 45°, refracting at 28°. Find refractive index.
3. For a concave mirror, u = -30 cm, v = -15 cm. Find f.

💯 Exam Tips & Strategies

• Memorize formulas for mirrors and lenses.
• Practice 10+ ray diagrams neatly labeled.
• Follow correct sign conventions for numericals.
• Write definitions and formulas in blue ink to highlight during exams.
• Attempt NCERT examples and exercise questions thoroughly.

🏫 Why Choose BACE IIT JEE?

At BACE IIT JEE, we focus on concept clarity and exam-smart preparation. Our experienced faculty ensure that students understand every topic deeply and apply it confidently during exams.

• Structured video lectures and concept sheets.
• Regular practice tests with solutions.
• Dedicated mentor support for each student.

📞 Contact Information

Telephonic Assistance:
For academic counselling, admissions guidance, and general enquiries, our team may be reached at:
+91-8969553036 | +91-7979942758 | +91-7061203824

🏢 Corporate Office:
HA-01, City Centre, Sector–4, Bokaro Steel City, Jharkhand
Located in the educational hub of the city for easy access and guidance.

© 2025 BACE IIT JEE | Empowering Bright Minds for Success