# Explain how a laser produces a beam of light that is different from the light produced by an ordinary light bulb.

> Eduqas A-Level Physics — 2.8 Lasers · Explain · 5 marks

> Lasers are used in many everyday applications, from barcode scanners to medical equipment. The light they produce has special properties that make it very different from the light emitted by an ordinary light bulb.

## Mark scheme (5 marks)

1. Laser light is coherent / all waves are in phase with each other
2. Laser light is monochromatic / all one wavelength or colour / single frequency
3. Laser light is a narrow, parallel / collimated beam that does not spread out
4. In a laser, atoms are stimulated to emit photons / light energy is released when excited atoms drop to a lower energy level
5. Ordinary light bulb produces light of many wavelengths / incoherent light / light spreads in all directions, whereas laser light does not

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