Chapter 15: Light

What is light in physics? Light is electromagnetic radiation that can be detected by the human eye. Electromagnetic radiation occurs over an extremely wide range of wavelengths, from gamma rays with wavelengths less than about 1 × 10−11 metres to radio waves measured in metres.

Light travels along a straight line

Light travels in a straight line because the diffraction effect is least due to the small wavelength of light. So the small wavelength of light produces negligible diffraction and therefore light travels along a straight line.