Light – Reflection and Refraction

Light: Verification of Laws of Reflection

Light: Verification of Laws of Reflection

Objective: To verify the laws of reflection. (Physics - Std 10)

Verify the fundamental **laws of reflection** on a plane mirror and explore related concepts such as the **angle of deviation**, which are crucial for understanding advanced optics.

Key Concepts and Laws

First Law of Reflection:

The **angle of incidence** ($$\angle i$$) is equal to the **angle of reflection** ($$\angle r$$). ($$\angle i = \angle r$$).

Second Law of Reflection:

The incident ray, the reflected ray, and the normal to the surface at the point of incidence all lie in the **same plane**.

Angle of Deviation ($\delta$):

The angle ($\delta$) by which a ray of light turns after reflection is the angle between the incident ray's direction and the reflected ray's direction. $$\delta = 180^\circ - 2i$$.

Experiment 1: Verification and Measurement

Simulate measuring the angle of incidence ($$\angle i$$) and observe the resulting angles.

Angle of Incidence ($$\angle i$$)
30°
Angle of Reflection ($$\angle r$$)
30°
Law Verified?
Yes ($$\angle i = \angle r$$)
Adjust the Angle of Incidence ($$\angle i$$) in degrees.

Experiment 2: Angle of Deviation ($\delta$) Challenge

Given the Angle of Incidence ($$\angle i$$), calculate the Angle of Deviation ($\delta$) in degrees. (Std 10 level challenge).

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Quiz Status
Deviation Formula
$$ \delta = 180^\circ - 2i $$
Nature of Image (Plane Mirror):

The image formed by a plane mirror is always **Virtual, Erect, Laterally Inverted,** and of the **Same Size** as the object. It is formed as far behind the mirror as the object is in front of it.

Introduction to Refraction (10th Std Context)

Reflection vs. Refraction:

Unlike reflection, where light bounces back into the same medium, **refraction** involves light **bending** as it passes from one medium to another (e.g., air to water). This is governed by **Snell's Law** ($n_1 \sin i = n_2 \sin r$).

Spherical Mirrors:

In 10th standard, we extend reflection to **spherical mirrors** (**concave** and **convex**), which form images by converging or diverging light rays.

Ray Diagrams:

The laws of reflection are visually represented using **ray diagrams**, which help trace the path of light and determine the position and nature of the image formed.

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