InterviewSolution
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InterviewSolution
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Monochromatic light falls on a right-angled prism at an angle of incidence 45^@. The emergent light is found to slide along the face AC. Find the refractive index of material of prism |
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Answer» Solution :Since the emergent light slides along the FACE AC, angle of emergence is `90^@`, as SHOWN. It implies that angle of INCIDENCE of the ray that falls on face AC is equal to the critical angle `theta_C`. `thereforer_2= theta_C ...(1)`  From the prism theory, we know ` r_1+r_2= A = 90^@ ` ` thereforer_2 = 90^@- r_1 ......(2)` fromequaiton(1) and (2)`,90^@ - r_1 =theta_c ` ` thereforesin( 90^@ -r_1) = sintheta_C(or)cos r_1= sintheta_C` Butsin ` theta_C = (1)/(mu )thereforecos r_1 = (1)/(mu)` Applyingsnell.slawat theboundaryAB , ` 1 xx sin45^@= mu sinr_1= mu sqrt(1- (1)/( mu^2))` ` therefore(1)/( sqrt(2)) = sqrt(mu^2 -1)or mu^2 = 3//2 = 1.5mu = sqrt(1.5)` |
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