Question

which of the following properties laser light has?
A) Laser light always lies in X-rays region
B) Laser light does not have directionality property
C) Laser light is white light
D) Laser light is highly coherent

Answer 1

Hint: Laser light has a unique property that waves of light are in phase of each other but waves produced by ordinary white light are not in the same phase.

Complete step by step solution:
Ultraviolet region for lasers consists of wavelengths between $180$ and $400nm$. Visible region consist of $400$ to $700nm$, it is the visible region and infrared region between $700$$nm$ to $1mm$. There is no laser part in the X-ray region.
So, the option $\left( A \right)$ is incorrect.

Laser light has directional properties, as this light has waves in almost perfect manner.
Laser light has directional property, but white light does not have. So, it is clearly different from white light.
Thus, options $\left( B \right)\& \left( C \right)$ are incorrect.
Lasers have a unique property which is coherency, it is the property of lasers that they have waves in phase.

So, the option $\left( D \right)$ is correct.

Note: Unique properties of laser which makes lasers unique than white light are- coherent, perfectly parallel waves and highly monochromatic. Monochromatic lights have only a single color.