Answer: The infra red waves is located between microwave and visible light based on their WAVELENGTH and FREQUENCY of occurrence.
Explanation:
Electromagnetic waves are those waves that do not require or need a material medium for its propagation, but they are able to travel through a vacuum. They exhibit or show all properties associated or connected with light. They are undeflected in electric and magnetic fields. These electromagnetic waves are arranged in order of their FREQUENCY and WAVELENGTHS which is known as ELECTROMAGNETIC SPECTRUM.
FREQUENCY is defined as the number of cycles which the wave completes in one second and is measured in Hertz(Hz). While WAVELENGTH is defined as the distance between two successive crests or troughs of waves which is measured in meter (m).
The electromagnetic spectrum is made up of the following rays which is arranged from the biggest wavelengths to the smallest:
--> Radiowaves
--> microwave :
--> infrared rays:
--> visible light:
--> ultraviolet rays
--> x-rays and
--> Gamma rays.
According to the arrangement of the spectrum above, the microwave has a higher wavelength and frequency than the infrared rays, while the visible light has a lower wavelength and frequency than the infrared rays.
Given :
The ball of a ballpoint pen is 0.5 mm in diameter and has an ASTM grain size of 12.
To Find :
How many grains are there in the ball?
Solution :
Volume of ball of the ballpoint is :

Now, grain size of 12 has about 520000 grains/mm³.
Therefore, number of grains are :

According to the inverse square law of light, <span>apparent brightness will decrease by a factor of 9. Use the formula </span>

, to check it.