Question

Several everyday objects are listed below. How does white light interact with each of these? Is it transmitted, reflected, absorbed or emitted? Explain how you know.

1. a light bulb that is on
2. a gallon of milk
3. a glass of water

Answer 1

Light is an electromagnetic wave having both electric and magnetic field perpendicular to each other. Light interacts with matter, and it can be reflected back, can be absorbed and can be emitted (by absorption electron in the core level jumps to highest atomic orbital and while coming back the inner orbital they will emit energy in the form of quanta or photon).

A) As light is made up of photons (packets of energy), these photons do not interact with each other, instead, they just pass through each other without being affected.

B). A gallon of milk is made up of tiny particles they interact with light and scatters in different directions as these particles move faster, the light also keeps hitting different particles in indefinite directions (Zig-Zag manner) and this process is called the TYNDAL effect. You could see the path of light passing through the milk.

C) Water is made of water molecules and suspended particles (ions, tiny impurities etc) and when light passes through this water, light interacts with water and the particles present and scatter the light or absorb depending on the type of suspended particles. Due to this scattering and absorbing effect only water appears blue is oceans.