Question

For the same angle of incidence , the angles of refraction in three media A,B and C are 150 , 250, and 350 respectively. In which media will the velocity of light be minimum

Answer 1

Nithya Gopinath answered this

We know that velocity of light in amedium is inversely proportional to the refractive index of the medium from the equation

  n = c / v  .............(1)

Moreover the refractive index of the medium is inversely proportional to the angle of refraction for the same angle of incidence from the equation

  n = sin i / sin r  ..............(2)

From (1) and (2) ,it is clear that velociy of light in a medium is directly proportional to the angle of refraction in that medium at a particular angle of incidence.

Thus the velocity of light is minimum in medium A  where the angle of refraction is minimum.

Sarvesh Kulkarni answered this

th

Sarvesh Kulkarni answered this

wa

Ankur Fogat answered this

Speed of light in a medium is inversely proportional to the refractive index of the medium. Since lesser the refraction angle, higher the refractive index, thus the speed of light is minimum in the last medium.

Harshita answered this

Answer is medium C
 

Sanya Anop answered this

Medium C

Reshma Ramadas answered this

In medium c as the angle of refraction is highest. hence its denser.therefore velocity is minimum.

Shruti Vyas answered this

Velocity will be minimum in medium A since , When ray of light goes from one medium to other, it deviates and deviation depends on whether media is more denser or rarer and alo on angle of refraction . That means angle of refraction will be less if it deviates more and it will be more if it deviates less . So on this basis we can say that velocity will be more in such media where angle of refraction will be less.

Answer 2

Hey There !

Answer: Speed is lowest in medium A (where angle = 15°)

We know that μ (Refractive Index) is inversely proportional to Velocity of light by the formula:

μ = $\frac{c}{v}$ ---( 1 )

 (c = speed of light in vacuum ; v = speed of light in the medium)

We also know by Snell's Law:

μ = $\frac{sin i}{sin r}$  -------( 2 )

Now, it is mentioned in the question, the incidence angle is same.

It is a mathematical property, that if the angle increases, the sine of the angle also increases.

Hence sin 15° < sin 25° < sin 35° -----( 3 )

Hence, putting (3) in (2) and comparing:

$\frac{sin i}{sin 15}$  >  $\frac{sin i}{sin 25}$  >  $\frac{sin i}{sin 35}$   ---( 4 )

{ Bigger the denominator, smaller the ratio