Electromagnetic radiation is a fundamental phenomenon of electromagnetism, behaving as waves and also as particles called photons which travel through space carrying radiant energy.

In a vacuum, it propagates at the speed of light, normally in straight lines. EMR is emitted and absorbed by charged particles. As an electromagnetic wave, it has both electric and magnetic components, which continuously oscillate perpendicular to each other and perpendicular to the direction of energy and wave propagation.

There are different types of electromagnetic waves. One of them are microwaves. You can even use microwaves to cook your food. Microwave ovens work by using microwave about 12.1cm wavelength to force water and fat molecules in food to rotate. The interaction of these molecules undergoing forced rotation creates heat, and the food is cooked

Microwaves used by Global Positioning System (GPS) receiver in your car, can also penetrate the canopy cover of forests to measure the soil moisture of rain forests. Most communication satellites also use other microwave bands to send signals to a ground station.

Microwaves that penetrate haze, light rain and snow, clouds, and smoke are beneficial for satellite communication and studying the Earth from space. The Sea Winds instrument onboard the Quick Scatterometer (QuikSCAT) satellite uses radar pulses in the Ku-band of the microwave spectrum. This scatterometer measures changes in the energy of the microwave pulses and can determine speed and direction of wind near the ocean surface.

Radar technology is considered an active remote sensing system because it actively sends a microwave pulse and senses the energy reflected back. Doppler Radar, Scatterometer, and Radar Altimeters are examples of active remote sensing instruments that use microwave frequencies

Passive remote sensing refers to the sensing of electromagnetic waves that did not originate from the satellite or instrument itself. The sensor is merely a passive observer collecting electromagnetic radiation. Passive remote sensing instruments onboard satellites have revolutionized weather forecasting by providing a global view of weather patterns and surface temperatures.

MRI is a medical imaging technique used in radiology to

investigate the anatomy and physiology of the body in both

health and disease.

The strength of a magnet in an MRI system is rated using a unit of measure known as a tesla. The magnets in use today in MRI systems create a magnetic field of 0.5-tesla to 2.0-tesla.

MRI OF SPINAL CORD

MRI OF ANKLE

MRI OF BRAIN

Most MRI systems use a superconducting magnet,

which consists of many coils or windings of wire through

which a current is passed, creating a magnetic field of

up to 2.0 tesla. Maintaining such a large magnetic field

requires a good deal of energy, which is accomplished

by superconductivity, or reducing the resistance in the

wires to almost zero.

To do this, the wires are continually bathed in liquid helium at

452.4 degrees below zero Fahrenheit. This cold is insulated by a

vacuum.

While superconductive magnets are used the strong magnetic

field formed allows for the highest-quality imaging.