An object appears to have a certain color because it selectively absorbs and reflects light. When we see an object as white, it means that it reflects all colors of the visible spectrum equally and does not absorb any particular color.
In the case of white light, it contains all the colors of the visible spectrum—red, orange, yellow, green, blue, indigo, and violet. When this white light falls on an object, the object's atoms and molecules interact with the incoming light. These atoms and molecules have certain energy levels associated with them.
When light interacts with matter, it can be absorbed, transmitted, or reflected. In the case of an object appearing white, it means that the object is reflecting all the colors of the visible spectrum equally. The atoms and molecules in the object do not absorb any particular color of light, and instead, they reflect all the incident colors back to our eyes.
The reason behind this phenomenon lies in the object's molecular structure and the energy levels of its atoms and molecules. The atomic and molecular structure of the object determines which colors of light are absorbed and which are reflected. In the case of a white object, the structure is such that it does not preferentially absorb any specific color, leading to equal reflection of all colors.
For example, if an object appears red, it means that it absorbs most of the colors of the visible spectrum and reflects only the red light. Similarly, objects that appear green absorb most colors except for green, which they reflect.
In summary, the reason an object does not absorb white light, despite containing all the colors of the visible spectrum, is that it reflects all colors equally. This is due to the molecular structure and energy levels of the object's atoms and molecules, which result in the object appearing white to our eyes.