JAMB - Physics (1986 - No. 41)
In fig 6, a ray of light in air strikes a glass plate at an angle of incidence 60 degrees, the reflected ray is observed to be perpendicular to the refracted ray, what is the refractive index of the glass
1.73
1.50
0.87
0.57
Explication
From the diagram above:
refractive index \(_gn_a\) = \(\frac{1}{_an_g}\) = \(\frac{sin r}{sin i}\) = \(\frac{ sin 30}{ sin 60}\) = \(\frac{1}{0.577}\) = 1.732