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The following materials are not used for the transmission and distribution of electrical power?
Copper
Tungsten
Aluminum
Steel
Tungsten
Tungsten is a refractory metal with an extremely high melting point (~3422┬░C) and high electrical resistivity, making it ideal for incandescent filaments but unsuitable for power transmission lines. Transmission and distribution conductors must have high electrical conductivity, low density, and high tensile strength, qualities possessed by Copper, Aluminum, and Steel (used in ACSR).
Tungsten is a refractory metal with an extremely high melting point (~3422┬░C) and high electrical resistivity, making it ideal for incandescent filaments but unsuitable for power transmission lines. Transmission and distribution conductors must have high electrical conductivity, low density, and high tensile strength, qualities possessed by Copper, Aluminum, and Steel (used in ACSR).
R=╧БAlтАЛ тАФ Resistance formula relating resistivity, length, and cross-sectional area
PlossтАЛ=I2R тАФ Power loss due to conductor resistance
The suitability of a material for transmission is governed by conductivity (╧Г), cost, and mechanical strength. Aluminum offers an excellent balance of low weight and conductivity, while Copper offers superior conductivity. Tungsten's high resistivity causes massive I2R energy losses and voltage drops, making it inefficient for long-distance power transfer.
Copper and Aluminum are primary materials for T&D due to high conductivity.
Steel is used as a core in Aluminum Conductor Steel Reinforced (ACSR) for mechanical strength.
Tungsten's resistivity is ~5.6 ├Ч 10┬░{-8} ╬йm,which is significantly higher than Copper (~1.68 ├Ч 10┬░{-8} ╬йm).
Transmission lines prioritize minimizing voltage drop and line losses.
Aluminum: Lightweight and cost-effective
Copper: High conductivity and ductility
Tungsten: High cost, high resistivity, brittle
Aluminum: Lower conductivity compared to Copper, higher expansion coefficient
Aluminum: Overhead transmission lines
Copper: Indoor wiring and transformer windings
Standard transmission conductors are typically ACSR or AAC (All Aluminum Conductor).
Tungsten is strictly used in high-temperature applications like light bulbs and arc welding electrodes.
B is correct тАФ Tungsten is not used in transmission and distribution due to its high resistivity and high cost, which would lead to prohibitive power losses.
Remember that materials used in power systems are selected based on the trade-off between conductivity, cost, and mechanical weight; refractory metals are rarely used for signal or power transport.