Question

2. A beam of light is travelling from air to glass medium. If the speed of light in air is 3 x 10 m/s and
refractive index of glass with respect to air is 2, calculate the speed of light in glass medium.


please guys answer correctly ​

Answer 1

Given:-

• Speed of Light in Air, v1 = 3× 10⁸ m/s

• Refractive Index of Glass with respect to air, n2 = 2

To Find:-

• Speed of Light in Glass Medium ,v2

Solution:-

Before going to Solve this Problem let's know about what's Snell's Law State ?

Snell's Law State that the ratio of angle of incidence to the sine of angle refraction is a constant for the given pair of media & colour of light .

The Refractive index of air is 1

According to Snell's Law

• Sin i/Sin r = n2/n1 = v1/v2

where,

n2 is the refractive index of glass with respect to air

n1 is the refractive index of air with glass.

v1 is the speed of light in vacuum/air

v2 is the speed of light in medium

Substitute the value we get

→ 2/1 = 3×10⁸/v2

→ 2×v2= 3× 10⁸

→ v2 = 3×10⁸/2

→ v2 = 1.5 × 10⁸ m/s

Therefore, the speed of in glass medium is 1.5 × 10⁸ m/s.

Answer 2

Answer:

$\huge \mathfrak {given}$

Speed of air (V1) = 3 × 10⁸ m/s

refractive index of glass with respect to air (n 2) = 2

$\huge \mathfrak {to \: find}$

speed of light in glass medium.

$\huge \mathfrak {answer}$

Here,

V1 = 3 × 10⁸ m/s

N1 = 1

N2 = 2

V2 = x

Here,

We will apply Snells law

${\huge {\boxed {\blue \: { \dfrac{ \sin(i) }{ \sin(r) } = \dfrac{n1}{N2} = \dfrac{v1}{v2}}}}}$

$\sf \implies \: \dfrac{2}{1} = \dfrac{3 \times 10 {}^{8} }{v2}$

$\sf \implies \: 2 \times v2 = 3 \times {10}^{8}$

$\sf \implies \: v2 = \dfrac{ {3 \times 10}^{8} }{2}$

${\huge {\blue {\bigstar {V2 = 1.5 \times 10⁸ m/s}}}}$

Here,

V2 = speed of light in glass medium

V1 = speed of light in air

N2 = refractive index of glass with respect to air

N1 = refractive index of air with respect to glass.