What colour will a red glass appear if it is heated in dark room?

[A] Total Internal Reflection
[B] Diffraction
[C] Scattering
[D] Refraction

Sereral laser with different are mixed so that their combined light apperars white. This light shines through a double slit onto a screen. John observes that the centre of the pattern on the screen appears ............

What colour fills in the blank, white or red or green or purple?

The index of refraction of flint glass is 1.66 and the index of refraction of crown glass is 1.52.

1. A film is formed by one drop of sassafras oil, on a horizontal surface of a flint glass block, is viewed by reflected light. The film appears brightest at its outer margin, where it is thinnest. A film of the same oil on crown glass appears dark at its outer margin. What can you say about the index of refraction of the oil?
   • It must be less than 1.52.
   • It must be between 1.52 and 1.66.
   • It must be greater than 1.66.
   • None of those statements is necessarily true.
2. Could a very thin film of some other liquid appear bright by reflected light on both of the glass blocks?
3. Could it appear dark on both?
4. Could it appear dark on crown glass and bright on flint glass?