Distinguish between metals
semiconductors and alloys on the basis of their temperature coefficient of resistivity values.
Answers
The resistance-change factor per degree Celsius of temperature change is called the temperature coefficient of resistance. A positive coefficient for a material means that its resistance increases with an increase in temperature.
Metals – These are solids which have very low resistivity or very high conductivity).
Hence, σ ~ 102 – 108 S/m
ρ ~ 10-2 – 10-8 Ωm
Semiconductors: A semiconductor remains partially full valence band and partially full conduction band at the room temperature The energy gap is narrower. These are solids which have resistivity or conductivity values between those of metals and insulators. Hence,
σ ~ 105 – 10-6 S/m
ρ ~ 10-5 – 106 Ωm
Alloys are metallic compounds composed of one metal and one or more metal or non-metal element.
Examples :
Steel, a combination of iron (metal) and carbon (non-metal)
Steel, for example, requires the right combination of carbon and iron (about 99% iron and 1% carbon, as it turns out) in order to produce a metal stronger, lighter and more workable metal than pure iron.
Answer:The resistance-change factor per degree Celsius of temperature change is called the temperature coefficient of resistance. A positive coefficient for a material means that its resistance increases with an increase in temperature.
Metals – These are solids which have very low resistivity or very high conductivity).
Hence, σ ~ 102 – 108 S/m
ρ ~ 10-2 – 10-8 Ωm
Semiconductors: A semiconductor remains partially full valence band and partially full conduction band at the room temperature The energy gap is narrower. These are solids which have resistivity or conductivity values between those of metals and insulators. Hence,
σ ~ 105 – 10-6 S/m
ρ ~ 10-5 – 106 Ωm
Alloys are metallic compounds composed of one metal and one or more metal or non-metal element.
Examples :
Steel, a combination of iron (metal) and carbon (non-metal)
Steel, for example, requires the right combination of carbon and iron (about 99% iron and 1% carbon, as it turns out) in order to produce a metal stronger, lighter and more workable metal than pure iron.
Explanation: