Whenever electric current flows through a conductor, the following three factors are present :
1. The pressure or potential difference V across the conductor (measured in volts) causing current to flow.
2. The opposition or resistance R of the conductor (measured in ohms) which must be overcome.
3. The current strength I (measured in amperes) which is maintained in the conductor as a result of pressure overcoming the resistance.
2. The opposition or resistance R of the conductor (measured in ohms) which must be overcome.
3. The current strength I (measured in amperes) which is maintained in the conductor as a result of pressure overcoming the resistance.
There exists a definite relationship between the three quantities involved and is known as Ohm's Law. It may be stated Thus :
"The ratio of potential difference (V) between any two points of a conductor to the current (I) flowing between them is constant, provided the temperature of the conductor doesn't change"
In other words, V/I = Constant or V/I = R
where R is the resistance of the conductor between the two points considered.
OR
" According to ohms law, the flowing through a conductor is directly proportional to the potential difference, across the ends of the conductor and inversely proportional to the conductor resistance."
i.e.., I α V and I α 1/R
where, I is the current, V is the voltage and R is the resistance of the conductor material.
thus
I α V/R
OR
"At constant temperature the current flowing through a conductor is directly proportional to the potential difference between its ends."
I α V ; V α I ; V = IR ;
Where R is a constant known as the resistance of the conductor.
OR
" The current is directly proportional to the voltage and inversely proportional to the resistance when the temperature remains constant."
i.e.., I = V/R
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