Answer:the resistance of a material is determined by its length, cross-sectional area, and resistivity
Explanation:Resistance is a measure of how difficult it is for electric current to flow through a material. There are several quantities that determine the resistance of a piece of material, including its length, cross-sectional area, and the material's resistivity.
Let's start with length. The longer a material is, the more resistance it will have. This is because a longer path means that there is more material for the current to travel through, which increases the likelihood of collisions between electrons and atoms. For example, a long copper wire will have more resistance than a shorter copper wire of the same cross-sectional area.
The cross-sectional area of a material also plays a role in determining resistance. The larger the cross-sectional area of a material, the lower its resistance will be. This is because a larger cross-sectional area means that there is more space for electrons to flow through, reducing the likelihood of collisions. For example, a thick copper wire will have less resistance than a thin copper wire of the same length.
Finally, the material's resistivity is a key factor in determining its resistance. Resistivity is a measure of how strongly a material opposes the flow of electric current. Materials with high resistivity, like rubber or glass, will have a high resistance, while materials with low resistivity, like copper or silver, will have a low resistance.
To calculate the resistance of a material, we can use Ohm's Law, which states that resistance is equal to voltage divided by current. The unit of resistance is the ohm (Ω).
In summary, the resistance of a material is determined by its length, cross-sectional area, and resistivity. By understanding these factors, we can choose materials and design circuits that minimize resistance and improve electrical efficiency.