User:Oluwamacy

 OHM’s LAW 

Ohm’s Law states that, the potential different (P.D) across a wire is directly proportional to the current that pass through it provided that temperature and other physical quantity or the condition of the conductor remain constant.

FOMULA TO FIND RESISTANCE

R=PL /A 

Where we’ve R as the Resistance

L as the Length

A as the Area

FOMULA TO FIND A

A=Pi•r2

FOMULA TO FIND CURRENT 

I = V/R

Where we’ve I as the Current

V as the Voltage

R as the Resistance

 EXAMPLE 

A copper wire has a length of 160m and a diameter of 1.00mm. If the wire is connected to a 1.5 - Volt Battery, how much current flows through the wire?

(For Copper, P = 1.72•10-8 Ohms

 SOLUTION 

R=PL /A 

L = 160m, V = 1.5V

For Copper, p = 1.72•10-8

I = ?

A=Pi•r2

= 3.14(0.005)2 = 7.85•10-7m2