Question

A rose appears red in white light as it absorbs red color and reflects all other colors. (State whether true or false).
a. True
b. False

Answer 1

Each color has a different wavelength and frequency .
there are different types of colors like primary colors, secondary colors etc.
Colours of an object detected by our eyes are those which are reflected by the object.

Complete answer:
A white light has seven colours Violet, Indigo, Blue, Green, yellow, Orange, Red. When white light is incident on an object, some of the colours are absorbed by the object and some of them are reflected back. Our eyes detect those colours which are reflected by our object toward our eyes.
Therefore a yellow object is absorbing all the colour except yellow. That yellow colour is detected by our eyes and we see it as yellow.
Rose red appears red in white light it means that all the colours of white light are absorbed except red. Hence the above statement is false. If rose absorbs red and reflects all other colors then it must be a combination of all other colours but not red.

Note: Even white light has seven colours but in nature we see a lot of colours not only these seven colours like grey, pink, etc. Their colours are actually the combination of two or more than two colours. It means that the object is absorbing all colours except those two or more colours of which colour of object is made of. If we want to see the colours of a white light we can use prisms. Prism disperse the white light into its constituent colours. Find this happens because white light consists of many wavelengths and for different wavelength refractive index is different. Deviation for different wavelengths would be different because deviation depends on the refractive index.