CBSE Class 10 Science Notes Chapter 10 Light Reflection and Refraction

CBSE Class 10 Science Notes: Chapter 10 - Light: Reflection and Refraction

Reflection of Light:

When light strikes a smooth surface, it bounces back. This is called reflection.
Law of Reflection: Angle of incidence = Angle of reflection.
Types of reflection: Regular (mirror) and Diffused (rough surface).

Refraction of Light:

Refraction is the bending of light when it passes from one medium to another.
The refractive index is the ratio of the speed of light in vacuum to the speed in the medium.

Lenses and Their Types:

Convex lens: A converging lens, focuses light to a point.
Concave lens: Diverging lens, spreads light apart.

Important Formulae:

Mirror formula: $\frac{1}{f} = \frac{1}{u} + \frac{1}{v}$
Lens formula: $\frac{1}{f} = \frac{1}{v} - \frac{1}{u}$

These notes summarize key concepts of light's behavior, including reflection, refraction, and lens properties. Understanding these concepts helps in solving numerical problems and applications in real-life scenarios.

Most Important Science Class 10 Questions Answers For Board Examination

Here are the top questions asked in the last 5 board exams from Chapter 10: Light - Reflection and Refraction:

Define the laws of reflection and explain their significance.
- Laws: The angle of incidence is equal to the angle of reflection, and the incident ray, reflected ray, and normal lie in the same plane.
What is the refractive index?
- It is the ratio of the speed of light in a vacuum to its speed in a medium.
Explain the working of a concave and convex lens with examples.
- Concave lens diverges light rays; used in glasses for myopia.
- Convex lens converges light rays; used in magnifying glasses.
Derive the mirror formula and use it to calculate image position.
What are the applications of refraction of light in daily life?
- Examples include the working of lenses in spectacles, cameras, and microscopes.

Most Important MCQs Science Class 10 For Board Examination

Here are some multiple-choice questions (MCQs) for Chapter 10: Light - Reflection and Refraction:

What is the angle of incidence if the angle of reflection is 30°?
- A) 60°
- B) 30°
- C) 90°
- D) 45°
Answer: B) 30°
What happens when light passes from air into water?
- A) It bends away from the normal
- B) It bends towards the normal
- C) It does not bend
- D) It gets absorbed
Answer: B) It bends towards the normal
The image formed by a concave mirror is always:
- A) Real and upright
- B) Virtual and inverted
- C) Virtual and upright
- D) Real and inverted
Answer: D) Real and inverted
The focal length of a convex lens is 15 cm. What is its power?
- A) +15 D
- B) -15 D
- C) +0.067 D
- D) -0.067 D
Answer: C) +0.067 D
Which of the following lenses is used to correct hypermetropia (far-sightedness)?
- A) Concave lens
- B) Convex lens
- C) Plano-convex lens
- D) Cylindrical lens
Answer: B) Convex lens