state the first law of refaction if the speed of light in a medium is 1.4 x 108 seconds find the refractive index
Answers
Answer:
There are 2 Laws of Refraction of Light:
• First law of refraction also called as ‘Snells’s Law’: This law tells us about the amount of bending of light rays. It says that the ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant.
• Second law of refraction: This law states that 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. If the light ray goes from medium 1 to 2 then the refractive index of medium 1 with respect to medium 2 is, where, v1 and v2 are the speeds of light in medium 1 and 2 respectively.
Explanation:
We know that, refractive index = speed of light in vacuum/speed of light in a medium. Let the speed of light in a medium be ‘n’
therefore, 1.5=3×10^8/n
1.5n=3×10^8,
n=3×10^×10/1.5×10
=30×10^8/15
n=2×10^8 m/s
Hence, speed of light in a medium is 2*10^8m/s
.
() . ' . , - / = ₁₂
, ₁₂ 1 2.
() , .
2 -
= 3 × 10⁸ /
= /
⇒ 1.5 = 3 × 10⁸/
⇒ = 2 × 10⁸ /
, 1.5 2 × 10⁸ /.