Answer :
X-rays .
These days have frequency ranging larger that ultraviolet but Lower than gamma rays .
Step by step explaination :
There are 7 types of crucial waves we study . they are arranged according to there effectiveness .
Let's study them accordingly .
- Radio waves : they have Lowest frequency with EM radiations . They are commonly used for conduction of signals from producer to reciever .
- Microwave : They are produced in vacuum, it is the second-lowest frequency waves in the EM spectrum.
- Infrared Waves : it is invisible light . The size of infrared waves ranges from a few millimeters down to microscopic lengths.
- Visible Light Rays : the wavelengths that are visible to most human eyes are called visible light rays .
- Ultra violet rays : Ultraviolet rays can be used to kill microbes.it is an invisible part of the "electromagnetic spectrum" .
- X-rays: they are penetrating radiation . Natural sources of x-rays include enormously energetic cosmic phenomena such as pulsars, supernovae and black holes.
- Gamma Rays :Gamma waves are the highest-frequency EM waves, and are emitted by only the most energetic cosmic objects.
Now you can see where the X rays comes .