Ohm’s law determines the relation between the potential difference and the flow of current. Therefore, Ohm’s law states that,
“ At constant temperature potential difference(V) is directly proportional to current (I)”
V∝ I
Verification of Ohm’s Law
At constant temperature, if we plot a graph of current versus potential difference, a straight line graph passing through origin is obtained.
Ohm’s Law: Graph
This shows that, potential difference increases with increase in current. In particulars, potential difference is directly proportional to the flowing current.
Ohm’s Law and Resistance
Ohm’s law states that potential difference is directly proportional to current.
V∝ I
V = IR
R= V/I
where R is constant of proportionality also, known as resistance.
Therefore, resistance is constant value obtained when potential difference is divided by current. Hence, resistance is defined as, “ Ability of conductor to resist the flow of charges through it ” Moreover, resistance is represented by R and is denoted by ohm Ω.
One Ohm Resistance
“A conductor is said to have resistance of one ohm if one ampere of current flows through one volt of potential difference.”
Relation between R and I
As talked earlier, Ohm’s Law is given as,
V = I R
Rearranging the equation of Ohm’s law,
I = V/R
This suggest that, at constant voltage current is inversely proportional to resistance. Therefore, by changing the value of resistance, value of current can be controlled. This effect is useful, because, it allows desired current to pass through the circuit without changing voltage source. Generally, Rheostat, a variable resistance device is attached with the circuit ti change the resistance of the circuit.
Comparison of material with respect to resistance
- Good conductors: Good conductors are those having low resistance and high conductivity. Generally, metals are good conductors. For example, Copper Aluminium, etc.
- Resistor: Resistor are the conductors that have high resistance and show moderate conductivity than good conductor. Generally, metal alloys are the resistor. For example, Nichrome, Nickel, etc.
- Insulators : Conductors which have very high resistance and no conductivity are insulators. Generally, non metals are insulators. For example, rubber, water, wood, etc.
Keywords: Ohm’s law, Verification of Ohm’s law, Potential difference, Current, Good conductors, Resistor, Insulator, Resistance, One Ohm resistance
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Ohm’s law essentially says the immunity of a component (commonly a resistor) is corresponding to the voltage dropped across the resistor divided by the current going right through it.This regulation can make it not too difficult to get certainly one of 3 principles: voltage across a resistance, the resistance value itself, or the current flowing through the opposition.