Question

explain a construction of newton's disc​

Answer 1

generally compact disc is newton's disc

Answer 2

Newton's disc is a disc with segments in painted in rainbow colours, i.e. violet, indigo, blue, green, yellow, orange and red, in that order.  When the disc is rotated, the colors fade to white;  Isaac Newton used this disc to demonstrate that white light is a combination of the seven different colours found in a rainbow.