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Resistance is directly-proportional to a material's length and resistivity, and inversely-proportional to its cross-sectional area.
In SI, length is measured in metres, cross-sectional area is measured in square metres, and resistivity is measured in ohm metres.
In North-American units, for conductors of circular cross-section, length is measured in feet, cross-sectional area is measured in circular mils, and resistivity is measured in ohm circular mils per foot (although, for some strange reason, it is often written as 'ohms per circular mil foot', which doesn't make much sense if you apply unit analysis!).
Note that resistivity is affected by temperature, so figures for resistivity are always quoted at specific (usual ambient) temperatures. So temperature indirectly affects resistance.
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Why is electrical resistivity important to a design engineer?
electrical resistance increases current flow decreases.so to know the current flow in the network ,electrical resistance is required.AnswerResistivity is important, because it is one of the three factors that affect the resistance of a material. The other factors are the length and cross-sectional area of the material.
Electrical resistance is a property of conductors that is measured in units of?
Ohm
What causes resistance to increase or decrease?
Voltage, if voltage is increased resistance in the circuit increasesAnswerResistance is determined by the length, cross-sectional area, and resistivity of a conductor. Resistivity is, in turn, affected by temperature -so temperature indirectly affects resistance.These are the only factors that affect resistance. Voltage and current have no direct effect whatsoever on resistance. Current can affect resistance indirectly if it causes the conductor's temperature to increase.For AC circuits, 'skin effect', due to frequency, causes the current to flow towards the surface of a conductor which acts to reduce the effective cross-sectional area of that conductor. So, frequency can also indirectly affect resistance.
What is the units of temperature coefficient of resistance?
The unit of temperature coefficient of resistance is ohm per ohm per degree Celsius or say resistance per resistance per degree Celsius.
How might ambient temperature may affect the resistance values you would measure in a circuit?
Ambient temperature might affect the readings of the resistance value you would measure because the resistance of some materials changes with the temperature.
Which of the factors below will not affect the placement of the PAPI units?
altitude
What are factors that affect viscosity and flow?
Pressure and temperature are the two factors that affect flow and viscosity. Viscosity refers to the resistance of a liquid to the shear forces.
What factors affect rock failure and resistance?
Hydrology Erosion Tectonic activity
What are factors that affect resistance of electricity?
Temperature, thickness, length and type of wire.
What factors affect the amount of air resistance acting on an object?
shape, size, and speed
What are the factors that affect resistance?
The factors are: length, cross-sectional area and nature of substance.
What three factors affect the amount of air resistance acting on an object?
shape, size, and speed
Factors affecting movement?
Three factors that affect movement are friction, wind resistance, and velocity. Friction is the resistance that a single object encounters when moving over another object. Velocity is speed, and wind resistance is the opposing force on an object.
What 3 factors affect the amount of air resistance on an object?
Speed, shape and frontal cross-section. Viscosity, texture, friction, gravity, velocity, size, and shape can all affect air resistance.
Two factors that greatly affect air resistance on falling objects are the size and what?
Frontal surface area.
What 3 factors affect the amount of air resistance acting on an object?
Speed, shape and frontal cross-section. Viscosity, texture, friction, gravity, velocity, size, and shape can all affect air resistance.
What factors affect how an object falls?
wind resistance, and gravity, mass does not in any way contribute to how an object falls.
