What is resistance and its unit?
What is resistance and its unit?
Resistance is the property of material to oppose the flow of electric current passing through it. Specific resistance is defined as the resistance offered by a unit length and unit cross-section of the substance to a current when a voltage is applied to it. Its SI unit is Ω−m.
What is the unit symbol?
Units and symbols
| Quantity measured | Unit | Symbol |
|---|---|---|
| Length, width, distance, thickness, girth, etc. | millimetre | mm |
| metre | m | |
| kilometre | km | |
| Mass (“weight”)* | milligram | mg |
Why is potential difference needed?
Electric potential difference is a measure of the strength of this force, divided by the amount of electric charge being acted upon. As such electric potential differences are needed to make electrons move, i.e. create electricity, because the potential represents the force needed to get past Newtons first law.
What are the factors affecting resistance?
Factors Affecting Electrical Resistance
- The cross-sectional area of the conductor.
- Length of the conductor.
- The material of the conductor.
- The temperature of the conducting material.
What is the mean of SI unit?
Système International
How units are written?
In writing, the names of SI units are always written in lowercase. However, the symbols of units named after a person are capitalized (e.g., ampere and A). Additionally, a space should always be included between a number and the SI unit, except for the degree symbol. Italics are usually not used with SI units.
Which is the best conductor of electricity?
Which Metal Conducts Electricity The Best?
| Material IACS (International Annealed Copper Standard) | ||
|---|---|---|
| Ranking | Metal | % Conductivity* |
| 1 | Silver (Pure) | 105% |
| 2 | Copper | 100% |
| 3 | Gold (Pure) | 70% |
What is ohmic resistance?
ohmic resistance – a material’s opposition to the flow of electric current; measured in ohms. electric resistance, electrical resistance, impedance, resistivity, resistance. electrical phenomenon – a physical phenomenon involving electricity. ohmage – the ohmic resistance of a conductor.
What is specific resistance and its unit?
Specific resistance is defined as “the resistance offered per unit length and unit cross-section area of that material when a known quantity of voltage applied at its end ”. The SI unit of specific resistance is Ohm-m.
What is SI unit of volume?
The SI unit of volume is the cubic meter (m3), which is a derived unit. Liter (L) is a special name for the cubic decimeter (dm3). The symbol for the liter is uppercase letter “ell” (L) is preferred to avoid the risk of confusion between the lowercase letter “ell” (l) and the number one (1).
What is potential unit?
The SI unit of electric potential is the volt, which is defined as a joule per coulomb. An atomic volt is defined as hartree per electron, approximately volts.
Does resistivity depend on length?
The resistivity of a material is the resistance of a wire of that material of unit length and unit cross-sectional area. The unit for resistivity is the ohm-metre. The resistivity of a material depends on its nature and the temperature of the conductor, but not on its shape and size.
Which conductor has highest resistivity?
Resistivity and Temperature Coefficient at 20 C
| Material | Resistivity ρ (ohm m) | Conductivity σ x 107 /Ωm |
|---|---|---|
| Silver | 1.59 | 6.29 |
| Copper | 1.68 | 5.95 |
| Copper, annealed | 1.72 | 5.81 |
| Aluminum | 2.65 | 3.77 |
What is the resistance of a wire?
Resistance describes how strongly a given cable opposes the flow of an electric current, and conductance measures a wire’s ability to conduct it. There are also two physical quantities associated with them – electrical resistivity and electrical conductivity.