Factors affecting resistance
Resistance is the property of a material that resists the flow of electric current through it. The following are some of the factors that affect resistance:
Material: Different materials have different resistivities, which determines how easily they allow the flow of electric current. Materials with higher resistivity have higher resistance.
Length: The longer the material, the greater the resistance. This is because the longer the distance that the electric current has to travel, the more resistance it encounters.
Cross-sectional area: The larger the cross-sectional area of the material, the lower the resistance. This is because a larger area provides more space for the electric current to flow through.
Temperature: The resistance of a material increases with temperature. This is because an increase in temperature causes the atoms in the material to vibrate more, which increases the resistance to the flow of electric current.
Presence of impurities: Impurities in a material can increase its resistance. This is because impurities can disrupt the flow of electric current through the material.
Presence of magnetic fields: A magnetic field can cause a material to exhibit resistance. This is because the magnetic field can induce an electric field within the material, which can create resistance.
Frequency: The resistance of a material can vary with frequency. This is particularly true for materials that are used in high-frequency applications, such as radio and television broadcasting.