Conclusion

In conclusion,

1. the property of white light is that it contains colours of the rainbow. Only by shining white light on the CD-R will there be rainbow colours observed. If a green or red laser light is shined onto the CD-R, only green or red light would be reflected accordingly.
2. due to refraction, the white light is separated into its constituent colours. This is because lights of different wavelengths have different speeds.
3. interference of light will determine the exact colours observed. The light observed will vary according to the angle at which white light is shined onto the CD-R and the bumps on the CD-R