LAWS OF REFLECTION AND LAWS OF REFRACTION(CBSE 10TH PHYSICS)

 

1. Laws of Reflection of Light

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

  • $$\angle i=\angle r$$

2. Laws of Refraction of Light (Snell’s Laws)

These apply when light passes from one medium to another (like from air to glass).
First Law:
The incident ray, the refracted ray, and the normal to the interface of two media at the point of incidence all lie in the same plane.
Second Law (Snell’s Law):
The ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant (for a given pair of media).

sini/sinr=constant=μ

• $$\frac{\mathrm{<br>}}{}$$
•   i= angle of incidence
• $r$ = angle of refraction
• $\mu$ = refractive index (e.g., glass with respect to air)
• When light travels from a rarer to a denser medium, it bends towards the normal.
• When light travels from a denser to a rarer medium, it bends away from the normal.