Voltage
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For a wire of uniform cross sectional area, the voltage drops in a uniform manner.
However, the voltmeter when connected calculates the difference between the two
points. Eg: if the voltage is 12V across the starting point of a wire, then the voltage at
the ending point will be 0 V. The voltmeter measures 12-0= 12V
For a wire of non-uniform length; the voltage doesn’t decrease at a uniform rate
Voltage is inversely proportional to area of cross section. As the area increases,
voltage decreases. There are less collision of charge carriers with the lattice ions,
leading to less loss of energy and less work.
Voltage is directly proportional to the length of the wire. The more the length of the
wire, the greater the presence of lattice ions across the length of the wire. As each delocalized electron drift through the wire, it does work by transferring electrical energy
into other forms. As it comes in contact with more number of lattice ions, more work
is done, so higher voltage.
Voltage and potential difference
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Voltage is the measure of work done/energy transferred by each coulomb of charge.
The voltmeter measures the voltage drop across a component.eg: if the voltmeter
measures 4V, then 4 J of energy is lost by each charge when passing through that
point.
The higher the resistance, the more the voltage drop.