Question

Which of the following transmission medium is immune from electromagnetic interference?
A. Category 3 shielded cable
B. Optical fibre
C. Coaxial cable
D. Category 5 twisted cable

Answer 1

The type of fibre which is a thin strand of glass that guides light along its length and has become the most widely utilised transmission medium for long-distance communications. LEDs are used as the light source in multimode fibre, which can carry signals over shorter lengths of up to $2\,\text{kilometres}$.

Complete answer:
Optical fibre transmission medium is immune from electromagnetic interference. Optical fibre is impervious to EMI. As a result, they are unaffected by Electro-Magnetic and Radio Frequency Interference. In other words, electrical noise in the environment has no effect on signal integrity.

Electrical noise can compromise the signal integrity in copper cables.The high cost of physical media and appropriate devices will be a result of fibre optics. The disadvantages are almost entirely installation-related; once established, fibre connections outperform typical copper cables in terms of electromagnetic interference immunity and bandwidth availability.

When magnetic field lines cut across conductors, they generate an electrical current. Because current cuts across the conductor in coaxial cables, electromagnetic interference occurs. Because signals are conveyed as light rather than current, fibre optics are immune to EMI.Optical fibre communication uses light from semiconductor (III-V) laser diodes as a transport. This light has a wavelength of $1.3 - 1.6{\text{ }}\mu m$ (infrared), which is undetectable to the naked eye.

Hence, the correct option is B.

Note: Fibre optic cable contains optical fibres coated in plastic that are used to convey data via light pulses. Heat, cold, and electromagnetic interference from other types of wiring are all protected by the plastic coating. Fibre optics transmit data more quickly than copper lines.