00:01
To the chapter geometric optics in which we have to determine the combination having smallest critical angle.
00:07
So for option a, we have light traveling from ice to diamond, ice to diamond.
00:14
So the critical angle of incident theta c, it is equals to arc sine n2 by n1.
00:22
N1 is the refractive index from where the race incidenting and n2 is the refractive index of the medium where ray is going.
00:31
So this is 1 and this is 2.
00:33
So refractive index of the ice is equals to 1 .310 and for the diamond it is 2 .417.
00:41
So hence we can say that the ray is going from lower refractive index to higher refractive index.
00:49
So the critical angle is not possible.
00:52
Critical angle is not possible.
00:55
Because we will get this value greater than 1 at sine in.
00:59
Inverse of greater than one value is not possible.
01:01
So now moving to the option b in which we have from quads to quartz to lew site.
01:10
So the refractive index of the quartz is equals to 1 .5 double four and for the lew site it is 1 .5.
01:18
So again we have refractive index here it is possible.
01:22
So from here after substituting value, so theta c it will be equals to arc sign 1 .5 divided by 1 .5 double 4 and this will be obtained as this will be equals to 76 .3 degree...