Question

why is board black answer​

Answer 1

Answer:

so that it can be called black board

Answer 2

because when white light is passed through it ,some colours are absorbed by the light and some are reflected .complementary colors such as blue and orange, red and green, or yellow and purple mixing blue and brown,these colours can be reflected by the light because when these colours are mixed together they form black colour.so when these colours are reflected we see black board is black in colour.