DEFINE RARER & DENSER MEDIUM. 

 We can distinguish the two types of medium in the following ways-

1.Speed of light is more in rare medium than dense medium

2.On entering dense medium light bend towards the normal in the plane while light bends away from the normal when it enters in rare medium

3. the most important difference is density of rare medium is less than that of dense medium

RM:- the optical medium in which the speed of light is  more. 

DM:- the optical medium in which the speed of loght is less.

 Angle of incidence in a denser medium,for which the angle of refraction in the rarer medium is 90^{0 .}

  We can distinguish the two types of medium in the following ways-

1.Speed of light is more in rare medium than dense medium

2.On entering dense medium light bend towards the normal in the plane while light bends away from the normal when it enters in rare medium

3. the most important difference is density of rare medium is less than that of dense medium

direction of propagation of light when travelling from one medium to another changes.so when direction of propagation light from air to water then it is called rarer medium.then d viceversa vl be d definion 4 d denser medium.hope it helps. thumbs up plseeeee

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