Which of the following is not an example of unguided transmission media?
Coaxial cable
Understanding Transmission Media in Data Communication
In the field of data communication, transmission media are the pathways that carry information from a sender to a receiver. These media can be broadly categorized into two main types: guided media and unguided media. The question asks us to identify which option is not an example of unguided transmission media. This means we are looking for an example of guided transmission media.
What is Guided Transmission Media?
Guided transmission media confine the signal to a specific physical path. The signal energy is contained within the solid medium, providing a physical conduit for data flow. Examples include various types of cables.
- Twisted-pair cable
- Coaxial cable
- Fiber-optic cable
What is Unguided Transmission Media?
Unguided transmission media, also known as wireless transmission media, transmit signals through the air, vacuum, or water. There is no physical conductor guiding the signal. The transmission relies on electromagnetic waves.
- Radio waves
- Microwaves
- Infrared waves
Analyzing the Given Options
Let's examine each option provided in the question:
- Radio transmission: This method uses radio waves to transmit signals through the atmosphere. Radio waves travel freely in space without being guided by a physical medium. Therefore, radio transmission is an example of unguided transmission media.
- Light transmission: This often refers to the transmission of data using light waves. While fiber-optic cable uses light (guided), wireless light transmission (like infrared communication or free-space optics) is considered unguided as light travels through the air. In the context of contrasting guided and unguided, "light transmission" as a standalone term usually implies the unguided form using electromagnetic spectrum in the light frequency range.
- Coaxial cable: This is a type of cable consisting of a central conductor surrounded by an insulating layer, a metallic shield, and an outer jacket. The signal is guided along the central conductor within the cable structure. This is a classic example of guided transmission media.
- Microwave transmission: This method uses microwave frequencies to transmit signals through the air, often requiring a line-of-sight path. Like radio waves, microwaves travel freely in space without a physical guide. Thus, microwave transmission is an example of unguided transmission media.
Identifying the Correct Option
Based on the analysis, radio transmission, light transmission (in the unguided sense), and microwave transmission are all examples of unguided transmission media. Coaxial cable, on the other hand, is an example of guided transmission media because it physically guides the signal along a cable.
The question asks for the option that is not an example of unguided transmission media. This corresponds to the option that is an example of guided transmission media. Coaxial cable fits this description.
| Medium Type | Description | Examples |
|---|---|---|
| Guided | Signal travels along a physical path. | Twisted Pair, Coaxial Cable, Fiber Optic Cable |
| Unguided | Signal travels through air/space as electromagnetic waves. | Radio Waves, Microwaves, Infrared |
Revision Table: Key Concepts
| Feature | Guided Media | Unguided Media |
|---|---|---|
| Signal Confinement | Confined to physical path (cable) | Propagates freely in space |
| Directionality | Direction determined by cable path | Broadcast or directional (line-of-sight) |
| Examples | Coaxial cable, Fiber Optic | Radio waves, Microwaves |
Additional Information on Transmission Media
Understanding transmission media is fundamental to network design and performance. Each type of medium has different characteristics regarding bandwidth, attenuation, interference susceptibility, and cost.
- Coaxial Cable: Offers higher bandwidth than twisted pair and better shielding against noise, making it suitable for longer distances and higher frequencies (e.g., cable TV, older Ethernet networks).
- Fiber-Optic Cable: Uses light pulses transmitted through glass or plastic fibers. Provides very high bandwidth, low attenuation, and is immune to electromagnetic interference, ideal for high-speed, long-distance communication.
- Radio Waves: Used for broadcasting, mobile communication, and wireless LANs. They can travel long distances and penetrate walls, making them versatile.
- Microwaves: Used for satellite communication, point-to-point links, and wireless LANs (like Wi-Fi). They have higher frequencies than radio waves and typically require line-of-sight due to their short wavelength.
Choosing the appropriate transmission media depends on factors like the required data rate, distance, cost, and environmental conditions. The distinction between guided and unguided media is based purely on whether a physical medium directs the signal propagation.
Important Questions from Miscellaneous
A stone is thrown horizontally from the top of a 20 m high building with a speed of 12 m/s. It hits the ground at a distance R from the building. Taking g = 10 m/s2 and neglecting air resistance will give :
A sphere of volume V is made of a material with lower density than water. While on Earth, it floats on water with its volume f1V (f1 < 1) submerged. On the other hand, on a spaceship accelerating with acceleration a < g (g is the acceleration due to gravity on Earth) in outer space, its submerged volume in water is f2V. Then:
A railway wagon (open at the top) of mass M1 is moving with speed v1 along a straight track. As a result of rain, after some time it gets partially filled with water so that the mass of the wagon becomes M2 and speed becomes v2. Taking the rain to be falling vertically and the water stationery inside the wagon, the relation between the two speeds v1 and v2 is :
Consider the following statements:
1. Distance between the longitudes becomes zero on North Pole and South Pole.
2. Distance between the longitudes is maximum on the Equator.
3. Number of longitudes is more than number of latitudes.
Which of the statements given above is/are correct?
One block of 2⋅0 kg mass is placed on top of another block of 3⋅0 kg mass. The coefficient of static friction between the two blocks is 0⋅2. The bottom block is pulled with a horizontal force F such that both the blocks move together without slipping. Taking acceleration due to gravity as 10 m/s2, the maximum value of the frictional force is :
