. A laser beam shines along the surface of a block of transparent material (see Fig. E33.8). Half of the beam goes straight to a detector, while the other half travels through the block and then hits the detector. The time delay between the arrival of the two light beams at the detector is 6.25 ns. What is the index of refraction of this material

n = 1,875

Explanation:

The speed of light in vacuum is constant (c) and in a material medium it is

          v = d / t

The refractive index of a material is defined by

         n = c / v

Let's look for the speed of light in the material, in general the length that light travels is known, this value is high, x = 1, when we place a block on the road, a small amount is lengthened by the length of the block, which in general is despised

These measurements are made on a digital oscilloscope that allows to stop the signals and measure their differences, that is, the zero is taken when the first ray arrives and the time for the second ray is measured,

         v = d / t

         v = 1 / 6.25 10⁻⁹

         v = 1.6 10⁸ m / s

we calculate the refractive index

        n = 3 10⁸ / 1.6 10⁸

        n = 1,875