Question

State the Laws of Reflection and Laws of Refraction of light.

Hint:

Reflection follows the rule \(i = r\), while refraction follows Snell's law \(\frac{\sin i}{\sin r} = \text{constant}\), which determines how light bends when it passes between two media.

Answer 1

Concept: Light is a form of energy that travels in the form of waves. When light encounters the boundary between two media, it may be reflected or refracted. The behavior of light during reflection and refraction follows specific laws known as the laws of reflection and the laws of refraction (Snell's law).
Step 1:Laws of Reflection of Light.
Reflection of light occurs when a ray of light strikes a surface and bounces back into the same medium. The laws of reflection are:

• First Law: The incident ray, the reflected ray, and the normal at the point of incidence all lie in the same plane.
• Second Law: The angle of incidence is equal to the angle of reflection.

Mathematically, \[ \angle i = \angle r \] where \(i\) is the angle of incidence and \(r\) is the angle of reflection.
Step 2:Laws of Refraction of Light.
Refraction of light occurs when a ray of light passes from one transparent medium to another and changes its direction due to a change in speed. The laws of refraction are:

• First Law: The incident ray, the refracted ray, and the normal at the point of incidence lie in the same plane.
• Second Law (Snell's Law): For a given pair of media, the ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant.

Mathematically, \[ \frac{\sin i}{\sin r} = \text{constant} \] This constant is known as the refractive index of the second medium with respect to the first medium.