Question

definition fo light......

Answer 1

Electromagnetic radiation that can produce a visual sensation (normally to humans). Though when some people talk about light, they are referring to whole electromagnetic spectrum, not just the visible part.

Answer 2

beam of ray

Answer 3

That portion of the electromagnetic spectrum visible to the human eye. It ranges from the red end to the violet end of the spectrum, with wavelengths from 700 to 400 nanometres and frequencies from 4.3 ´ 1014 to 7.5 ´ 1014 Hz. Like all electromagnetic radiation, it travels through empty space at a speed of about 186,000 mi/sec (300,000 km/sec). In the mid-19th century, light was described by James Clerk Maxwell in terms of electromagnetic waves, but 20th-century physicists showed that it exhibits properties of particles as well; its carrier particle is the photon. Light is the basis for the sense of sight and for the perception of colour.(from answers.com)

http://library.thinkquest.org/C005705/English/Light/light1.htm