Is current directly proportional to length?
In fact, the electromotive force V (measured in volts) across a circuit divided by the current I (amperes) through that circuit defines quantitatively the amount of electrical resistance R. The resistance of a wire is directly proportional to its length and inversely proportional to its cross-sectional area.
Why resistance is directly proportional to the length of the conductor?
As the length increases, the number of collisions by the moving free electrons with the fixed positive ions increases as more number of fixed positive ions are present in an increased length of the conductor. As a result, resistance increases.
How does resistance change if the length of the wire is increased?
when you have longer length of wire, the current has to travel more distance, more the distance higher the number of obstacles it faces through its path. Therefore resistance increases with the length. When cross sectional area increases the space of the elctrons to travel increases(simply explained).
How do you find resistance in area?
its cross-sectional area A – the greater the area, the less its resistance. the resistivity of the material r – the greater the resistivity, the greater its resistance….resistivity = resistance × area / length.
| Map of contents | Close |
|---|---|
| Introduction | 3. Efficient motors |
| 1. Using electricity | Using electric motors |
How do you find the minimum cross-sectional area?
Try formula sq rt I squared x t divided by k and it gives you 1.88 so nearest cpc size is 2.5mm. So a minimum CSA of 2mm is required, 2.5mm is the correct answer.
Does resistivity depend on length and diameter?
The resistivity of a material is the resistance of a wire of that material of unit length and unit cross-sectional area. The resistivity of a material depends on its nature and the temperature of the conductor, but not on its shape and size.
Why does resistivity increase with length?
When electrons start to move, they get scattered from the nuclei present in the material which is the wire made from. This process creates the resistance. Thus, when the length of the wire increases, the amount of particles scattered from the nuclei increases which also increases the resistance.