OHM’S LAW

 OHM’S LAW

German physicist George Simon Ohm 

found that “voltage, current and resis-

tance” are related to each other and derived 

a law. This is called Ohm’s law. Let us 

try to understand ohm’s law through the 

example shown in Figure

1. From top hole, water flows with a 

low speed. Because, only air pressure 

and gravity act on it.

2. Water from the middle hole flows 

with increasing speed than in the 

top hole, because pressure increases 

due to water in the top portion of 

the bottle along with air and gravity.

3. Water from the bottom hole flows 

with high speed than in the first and 

middle, because pressure increases 

due to water in the top and middle 

parts along with air and gravity.

Likewise, in a circuit, if the sup-

ply voltage increases, the electric current 

increases. If the supply voltage decreases, 

current also decreases (Resistance value 

should be constant in both the conditions)

I ∝ V

Therefore, the current in a circuit can be 

represented as,

I ∝V I___

R