Resistance is the property that obstructs the flow of electrical current in a circuit. The potential difference, or voltage, across two points in a circuit can be used to calculate the amount of energy transferred. In this guide, we'll teach you how to calculate the resistance per cm of a specific wire by plotting a graph of voltage versus current.
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The aim of this experiment is to calculate the resistance per cm of a given wire by plotting a graph of voltage versus current.
Ohm’s law states that the current flowing through a conductor is directly proportional to the voltage across it, provided the physical conditions (pressure, temperature, and dimensions) of the conductor remain constant.
If I is the current flowing through the conductor and V is the voltage across it, then
and hence
V = RI
Here, R is the constant of proportionality and is known as the electrical resistance of the conductor. The resistance R is dependent on the dimensions and material of the conductor. The relationship between the resistance of a material, its length, and cross-sectional area is given by the formula
Here, ρ represents the specific resistance or resistivity, which is a characteristic of the material of the wire.
Range of ammeters = _____ mA to _____ mA
The least count of ammeter = _____ mA
Range of voltmeter = _____ V to ____ V
The least count of voltmeter = _____ V
The least count of meter-scale = _____ m
Length of the given wire, l = _____ m
| S. No | The applied potential difference
(voltmeter reading V ) |
Current flowing through the wire
(Milliammeter Reading A ) |
2. Calculate the slope of the graph. The resistance of the given wire is the reciprocal of the slope.
From the graph, R = BC / AB = _____ Ω
3. Resistance per unit length of the wire = R/t = _____ Ωm –1
Error Analysis
Here, R is the resistance per unit length and Δ R is the estimated error. Δ V and Δ I are the least count of voltmeter and ammeter respectively.
The potential difference across the wire is linearly related to the current.
The resistance per unit length of the wire is ( R ± Δ R ) = _____ ± _____ Ωm –1 ).
1. What is Ohm’s Law?
Answer:
Ohm’s law states that the current flowing through a conductor is directly proportional to the voltage across it. The constant of proportionality is the resistance, denoted by R . So, Ohm’s law can be written as V = IR .
2. What factors does the resistance of a conductor depend on?
Answer:
The resistance of a conductor depends on the following factors:
3. What is a rheostat?
Answer:
A rheostat is a device that allows you to vary the resistance, which in turn controls the current flow.
4. What is the shape of a V vs I graph for a linear resistor?
Answer:
The graph of voltage versus current for a linear resistor is a straight line.
5. What is the reciprocal of resistivity called?
Answer:
The reciprocal of resistivity is called conductivity.
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Related Articles: |
What is Ohm’s Law?
Ohm’s law states that the potential difference across an ideal conductor is proportional to the current through it. The constant of proportional is known as the resistance R. Ohm’s law is given by V = IR.
Which factors do the resistance of a conductor depend on?
The resistance of a conductor depends on the following factors: Resistivity, Length, Temperature, Cross-sectional area.
What is a rheostat?
A rheostat is a variable resistance that is used to control the current.
What is the shape of a V vs I graph for a linear resistor?
The shape of the V vs I graph for a linear resistor is a straight line.
What is the reciprocal of resistivity called?
The reciprocal of resistivity is called conductivity.