A compass relies on Earth's magnetism to stay pointed north.
electro magnet
Everything that you plug into the wall works because the electric field is what moves electron from point A to point B. Any optical(mirror, lens, radar ....) device works because of property of light. Light is a EM wave, and most device bend or reflect light by manipulating how the electric field component of the light wave behave.
lets say if you were to suspend a bar magnet freely it wouldn't just swing around. it would line with the north and south pole that's how a compass works
Kymograph. Don"t ask me how it works- also used to track RF radio frequency waves.
The earth and the rock both pull each other, with equal force, because of the way gravity works. We don't really know how, but we do know that any two masses always attract each other with equal forces that depend on the product of the two masses and the distance between them.
electro magnet
Digital Data is data that is stored in binary, and a Digital Device is any device that works with binary data
A Touchscreen Monitor will work as an input and output device
Any digital device - as opposed to an analogue device.
Any electrical device that emits Light
analog
The term "load" when used in electrical terminology is a device that uses electricity.
archimedes' principle
Define BJTSRAM?
A router.
A good example of an input and output device is a touchscreen monitor.
Try www.loc8tor.com It is a homing device for lost articles such as keys, glasses etc. Not sure if it works off a satellite. Who cares, as long as it works.