Notes

the lowest frequency radio waves are used in radios or FM Radio (application 1) and radio frequency ID (RFID) is a tiny chip that stores information about for example a book, if you take the book out, the security will know whether the book is legally of illegally taken out. It can also be used in humans, for example, people use these on their skin for travel. ALL ELECTROMAGNETIC WAVES TRAVEL IN Streight LINE but if they encounter an edge, they will diffract but the edge must be comparable and not something small
2nd lowest frequency microwaves are used in microwaves for cooking and it is used in mobile phones well (these are major applications)
They have lower wavelengths and they will be diffracted from small openings. they are also used in tv (satellite broadcast). waves are a way of energy thus radio waves have low energy but gamma rays have the most energy stored. microwaves which are in mobile phones are hazardous to us.
infrared rays have high frequency which is used in remote controls (they are beams of light) imagine if you're going to a restricted area and u will see a barrier u will use a different rout but if u use infrared ray, they will not see the beam and if he crosses the beam the alarm will be set off so, it is used in security. another aplication is infrared imaging which is making an image from infrared because every hot object emits infrared and infrared cameras make an image even at night because all they need is temperature (night vision cameras)
visible light is used in seeing, fiber optic and more things like that
ultraviolet light is very dangerous