An ammeter can be used as a voltmeter if used in conjunction with a resistor of known resistance (preferably large resisitance).berkeman said:
I know how to use a voltmeter and a resistor together as an ammeter, but I never thought about using an ammeter and resistor as a voltmeter. How does that work? Oh, I get it -- but the resistance of the ammeter degrades the accuracy of the measurement. I guess that's why you said to use a large value of external resistor...Chi Meson said:
Resistivity is a measure of how much a material opposes the flow of electric current. In the context of a wire, it refers to the wire's ability to resist the flow of electrons through it. It is directly related to a wire's length, cross-sectional area, and material.
The resistivity of a wire can be calculated using the formula ρ = RA/l, where ρ is resistivity, R is the resistance of the wire, A is the cross-sectional area, and l is the length of the wire. It is important to use consistent units, such as meters for length and ohms for resistance, in order to get an accurate result.
The resistivity of a wire is affected by its length, cross-sectional area, and material. A longer wire will have higher resistance and therefore higher resistivity. A wire with a smaller cross-sectional area will also have higher resistance and resistivity. Different materials have different resistivities, with some materials being better conductors than others.
The resistivity of a wire is important because it affects the wire's ability to conduct electricity. A wire with high resistivity will have more difficulty conducting electricity, resulting in a higher resistance and potentially causing issues in electrical circuits. Understanding the resistivity of a wire is crucial for designing and building efficient and safe electrical systems.
In general, as the temperature of a wire increases, its resistivity also increases. This is due to the increased vibration of the atoms in the wire, which creates more obstacles for the flow of electrons. This effect is more pronounced in some materials, such as metals, than others. Therefore, it is important to consider temperature when calculating the resistivity of a wire in order to get accurate results.