Question

The properties of light can be best explained by assuming that light is composed of:
I) Particles
II) Waves
III) Atoms

A) I only
B) II only
C) I and II
D) II and III

Answer 1

To answer this question, you should recall the concept of properties of light. The major properties of light include interacting with a matter like reflection, refraction, photoelectric effect.

Complete step by step solution:
You should remember that Quantum theory of atomic particles that describes matter and light consists of minute particles that have properties of waves that are associated with them. Light is made up of small packets of energy known as photons and matter is made up of particles known subatomic particles known as protons, electrons, and neutrons. Each particle shows dual nature i.e. both wave and particle nature.
There are a few characteristic properties of light in which it shows wave nature like diffraction, interference.
There are also a few properties of light in which it shows particle nature, like photoelectric effect.
Thus, we can conclude that:
Light has a dual nature: light travels in straight lines (particle nature) and shows diffraction as well(wave nature).

Hence, the correct option is C.

Note:
An important aspect of quantum theory is Heisenberg’s uncertainty principle. To understand Heisenberg’s uncertainty principle in a better way, consider an example where the position of an electron is measured. Now to measure the position of an object, we need light, so a photon must collide with it and return to the measuring device. We know that photons hold some finite momentum, a transfer of momenta will occur when the photon collides with the electron. This transfer of momenta from photon to electron will cause the momentum of the electron to change. This would mean that an attempt at measuring the position of a particle will cause uncertainty in the value of its momentum. Heisenberg’s uncertainty principle has a negligible impact on macroscopic objects as the mass of a ball is much larger than that of an electron.