White light through a glass prism

In the picture

1. 1Narrow white beam entering the left face: one white ray before the glass.
2. 2Triangular glass prism: a clear solid with three flat faces.
3. 3Widening fan leaving the right face: colours spread from red to violet.
4. 4Coloured band on the pale panel: a smooth strip from red through violet.

Examples

• A rainbow after rain.
• Small rainbow patches from sunlight through a cut-glass ornament.

Quiz: White light through a glass prism (Age 15)

1. 1

   When white light passes through a glass prism, what happens to it?

   • It changes into only one colour inside the prism.
   • It stays as a single white beam after leaving the prism.
   • It separates into a continuous band of colours.
2. 2

   Why do the colours in white light separate when they pass through a glass prism?

   • All colours bend by the same amount in glass.
   • Different colours bend by different amounts in glass.
   • The prism adds new colours to the white light.
3. 3

   What does the separation of white light into a continuous coloured band show about white light?

   • White light is a mixture of many colours.
   • White light is a single colour that only looks white.
   • White light is made of only red and violet.

The answers, each with its explanation, are in the app. This lesson has left the free week, so its quiz is part of the subscription.