The electromagnetic radiations are stream of photons travelling in waves through vacuum. That is, they don’t need any medium to travel unlike sound waves. An electromagnetic spectrum consists of all forms of electromagnetic radiations arranged from lowest energy (longest wavelength) to highest energy (shortest wavelength).
High frequency electromagnetic waves are used in medical and engineering fields.
We need Ultraviolet or UV rays to synthesize vitamin D in our body. These are the invisible rays that come from sun and they are the cause of tan on our skin. An overdose of UV absorption can cause skin cancer in addition to causing wrinkles. Earth’s ozone layer absorbs these UV rays from sunlight before reaching earth. But as this layer is getting depleted with time, it is not able to block them. Hospitals use UV rays to sterilize surgical equipments and kill microbes. We dry our clothes in sunlight in order to prevent infection due to bacteria.
X-rays are high frequency rays that are very much useful in medical field to examine inner parts of our body. The part that absorbs x-rays leaves white patches on the film depicting that part. They are also used in airport security checks to see through our baggage. Since different material absorbs different amount of x-rays, image lets the security to see distinct items. X-rays are given off by stars and are present in the outer space but they don’t come into earth.
Gamma rays are extremely high energy radiation that passes through most materials, even thick sheets of dense material like lead. Gamma rays also come from sun. In industries, they are used to inspect welds. Correct dose of gamma rays kills cancer cells and an overdose leads to death.
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