Question

Give the range of wavelength of the electromagnetic waves visible to us
$\left( a \right)1000{{\text{A}}^{\text{o}}}\,to\,4000{{\text{A}}^{\text{o}}}$
$\left( b \right)4000{{\text{A}}^{\text{o}}}\,to\,8000{{\text{A}}^{\text{o}}}$
$\left( c \right)8000{{\text{A}}^{\text{o}}}\,to\,9000{{\text{A}}^{\text{o}}}$
$\left( d \right)400{{\text{A}}^{\text{o}}}\,to\,\,800{{\text{A}}^{\text{o}}}$

Answer 1

As the question clearly asks about the visible range of a spectrum then we can say that the visible one means the colors that are sensitive to our eyes. We will consider the light spectrum of all types of rays and choose the visible one and write its range in Angstrom.

Complete step by step answer:
Electromagnetic waves: These types of waves are magnetic in nature and contain an amount of electric component in them which needs a median to bring the light into energy. These exist in nature having different frequencies. In short, these frequencies have a continuous range which is what we call an electromagnetic spectrum. The series of it is in the following form with the longest wavelength on the left to the smaller wavelength to the right.
Radio > Microwaves > Infrared > Visible > Ultraviolet > X-Rays > Gamma rays.
The diagram shown below is known to us by the visible light spectrum.

These are the colors which can be seen through normal eyes. This spectrum consists of the amount of wavelengths starting from 700nm to 400nm. This visible spectrum is also seen in the rainbow having a sense of colors in the form of VIBGYOR, where V is violet, I is indigo, B is blue, G is green, Y is yellow, O is orange and R is red. When all these colors are mixed to one then they form a white light which we can see easily. Our eyes can see the visible range of this spectrum and this ranges up to $4000{{\text{A}}^{\text{o}}}\,to\,8000{{\text{A}}^{\text{o}}}$.

So, the correct answer is “Option B”.

Note: If one wants to see such visible spectrum in real then either they can see it in rainbow or with the help of prism. We only need to just place the prism in front of the rays of sunlight in such a manner that the rays get passed through the prism. If the prism is on a white type of a surface then we can clearly see the dispersion of light into the similar spectrum as visible one. It is called visible because our eyes are sensitive to this range. If the question asked about the visible range in nanometers then the answer would be 700nm to 400nm.