Applications of Electromagnetic Waves

Applications

1. Superconducting Power Transmission

• For power transmission at superconducting temperatures, hollow conductors with coolant and thermal insulation are used. This application is based on the concept of skin depth in conductors. The superconductivity always require refrigeration. Consider a hollow conductor with coolant passed throughout to maintain its super-conductivity by keeping the temperature of cable very low.

• At superconducting temperatures the conductivity of conductor is very high and also the skin depth for current to exists is very small, the current flow through only outer surface of conductor. It is very much similar to a thin film of a superconducting material on a metallic tube in liquid helium or nitrogen. Above system is very useful to transmit huge amount of power with practically very little losses. This system finds application in area of power generation and distribution. 

2. Fiber Optic Magnetometer

• The optical fibers can be effectively used for the measurement of very low magnetic fields. Two long, identical length optical fibers are connected to same light source as shown in the Fig. 10.12.2. One of the fibers is coated with magnetostrictive material.

• In the obsence of any surrounding magnetic field, the paths of light are identical and the output of two fibers is in phase and hence output of phase detector will be zero.

• But with surrounding magnetic field, the length of a fiber coated with magnetostrictive material changes and the fiber gets contracted. Note that this change in the length is very small. But even though the length is very small, the phase changes considerable giving non-zero output.

Review Question

1. Explain few applications of electromagnetic waves.