Practice Question

1.White light travels from an object to a magenta filter. When a person looks at the magenta filter what colour do they see the object to be?

Magenta (red and blue)

2. Blue light travels from an object to a Magenta filter. When a person looks at the magenta filter what colour does the object appear to be?

Magenta contains red and blue as it is a secondary colour. A magenta filter will transmit blue light. So, the object will appear blue. 

3. White light passes through a blue filter before striking a white ball. The reflected light from the ball then strikes a red filter. A person then looks at the red filter. What colour does the ball appear to be in the red filter?

When white light passes through the blue filter, the blue filter absorbs all of the wavelengths of light apart from blue. So, blue wavelengths are transmitted and strike the white ball. 

The white ball will not absorb any wavelengths, but it will reflect the blue wavelengths which then strike the red filter. 

The red filter will absorb the blue wavelengths and transmit no light. So, the object appears black.