The correct sequence of increasing order of electrical resistivity of the given material is-
Gold, Doped Germanium, Silicon, Diamond
Electrical Resistivity Ranking
Electrical resistivity is a fundamental property of a material that quantifies how strongly it resists the flow of electric current. Materials are broadly classified into conductors, semiconductors, and insulators based on their electrical resistivity. Conductors have very low resistivity, allowing current to flow easily. Insulators have very high resistivity, effectively blocking current. Semiconductors have resistivity values between those of conductors and insulators, and their resistivity can be significantly altered by factors like temperature or the addition of impurities (doping).
Understanding Material Classification and Resistivity
To determine the correct increasing order of electrical resistivity for the given materials (Gold, Silicon, Doped germanium, Diamond), let's categorize each one:
- Gold: Gold is an excellent metal conductor. It has a very low electrical resistivity, allowing electricity to flow through it with minimal resistance.
- Silicon: Silicon is a semiconductor. Its resistivity is much higher than that of conductors but significantly lower than that of insulators. In its pure form, Silicon has a resistivity that allows it to conduct electricity under certain conditions.
- Germanium (Doped): Germanium is also a semiconductor, similar to Silicon. However, the term "doped germanium" is crucial. Doping involves intentionally adding impurities to a semiconductor to increase its conductivity. Doping significantly decreases the electrical resistivity of a semiconductor compared to its pure form, making it a better conductor. Germanium typically has a smaller band gap than silicon, meaning that for pure samples, germanium would generally have lower resistivity than silicon. With doping, its resistivity decreases even further.
- Diamond: Diamond is an excellent electrical insulator. It has an extremely high electrical resistivity, meaning it resists the flow of electricity very strongly.
Comparing Electrical Resistivity Values
Let's compare the materials based on their typical resistivity ranges:
| Material Type | Example Material | Typical Resistivity (Ohm-meter, $\Omega \cdot m$) |
|---|---|---|
| Conductor | Gold | $\sim 10^{-8}$ |
| Doped Semiconductor | Doped Germanium | $\sim 10^{-3}$ to $10^{-6}$ (Lower than pure semiconductor) |
| Semiconductor | Silicon | $\sim 10^{-3}$ to $10^{3}$ (Higher than doped, lower than insulator) |
| Insulator | Diamond | $\sim 10^{13}$ to $10^{18}$ |
Based on this comparison and the understanding of how doping affects semiconductors:
- Gold has the lowest electrical resistivity because it is an excellent conductor.
- Doped Germanium comes next. While Germanium is a semiconductor, doping significantly lowers its resistivity, making it more conductive than pure silicon. Germanium generally has lower intrinsic resistivity than silicon due to its smaller bandgap.
- Silicon has a higher electrical resistivity than doped germanium. It is a semiconductor but without doping, its conductivity is lower than that of its doped counterpart.
- Diamond has the highest electrical resistivity by far, as it is a superb insulator.
Final Order of Increasing Resistivity
Therefore, the correct sequence of increasing order of electrical resistivity is:
Gold < Doped Germanium < Silicon < Diamond
This means Gold has the lowest resistivity, followed by Doped Germanium, then Silicon, and finally Diamond has the highest resistivity among the given materials.
Important Questions from Resistivity of Various Materials
Which of the following has the highest value of resistivity?
What is the correct sequence of resistivity of silver, nichrome and glass at room temperature?
Which of the following graph correctly represents the variation of resistivity 's' with temperature 'T' for a semiconductor material ?
- Resistivity of a conductor depends on
