# Is it Zircon or Diamond?

## Explanation:

To determine if the substance is zircon or diamond when the wavelength of light in the solid is 329 nm and it comes from a He-Ne laser with a wavelength of 633 nm in air, we need to use the concept of index of refraction.

The index of refraction (n) can be calculated using the following formula:

**n = Î»air / Î»solid**

Where Î»air is the wavelength of the laser in air (633 nm) and Î»solid is the wavelength of the laser in the solid (329 nm).

Plugging the numbers into the formula gives us:

**n = 633 nm / 329 nm = 1.924**

Therefore, the index of refraction of the solid is approximately 1.924.

Since the index of refraction for zircon is 1.923, as given in Table 25.1, and the calculated index of refraction of the unknown solid is approximately the same, the substance is likely zircon.