The following table given the value of the angle of deviation for different values of the angle of incidence, for a triangular prism : Angle of incidence 33°, 38°, 42°, 52°, 60°, 71° Angle of deviation 60°, 50°, 46°, 40°, 43°, 50° (a) For what value of the angle of incidence, is the angle of emergence likely to be equal to the angle of incidence itself

Dear Student,

Please find below the solution to the asked query:

    In the experiment of prism, we check the values of deviation for different values of incident angles. Before going to plot the graph with given values, here i want to mention the relation of incident angle and the angle of deviation. These two parameters are related according the following relation.
δ = i+e-A
δ = Angle of deviation,
i = Angle of incidence,
e = Angle of emergence,
A = Angle of prism.
   According to the condition, If the angle of incidence is equal to angle of emergence, then the angle of deviation is minimum.
δmin=2i - A
Here if we plot the graph ( in below figure i plotted), 

we can observe that δmin=400 is at an incident angle i = 520.
So, Angle of emergence and Angle of incidence are equal and their values are,
i = e = 520

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  • 13
For 52° angle of incidence and angle of deviation is minimum that is 40°. And in that case angle of incidence is always equal to angle of emergence.
  • 11
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