OHM'S LAW

 

The Ohm's Law is named after a German physicist George Simon Ohm, who discovered it. It involves three variables:
    1. E for voltage (volt)
    2. R for resistance (ohm)
    3. I for current (ampere)

For any of the two known quantities in the circuit (voltage, current, resistance), we can calculate the third quantity. The Ohm's Law can be written in several ways. The most basic form is:

E = I 5 R

Other equations that are derived from this basic equation are:
    1. I = E/R
    2. R = E/I

There is a mnemonic to help solve the Ohm's Law equation.

(insert pictures p. 33,34)

 

Example exercises:

    1. Given that R = 0.5 Ohms and E = 10 Volts, find I.

      2. Solution: I = E/R

      I = 10/.5 = 20 A

       

    2. Given that I = 200 Amps and R = 100 Ohms, find E.

Solution: E = IR

E = 200 5 100 = 20000 volts