Ohm’s LawBy Ohm’s Law ..
- The symbol is I .
(for example I=5 A or I=5 amps) .
- Current cannot flow without voltage .
Current :
Voltage :
- It is a measure of the energy carried by the charge .
- It attempts to make a current flow .
- The Symbol is : V or E .
- It is described as a “push” of the electric current .
- It is measured in Volts (V=1.5v) .
Voltage :
- The symbol is R .
- It is measured in ohms .
Resistance :
Ohm's Law :
- To make a current flow through a resistance there must be a voltage across that resistance .
- Ohm's law shows the relationship between the voltage (V), current (I) and resistance (R) .
- V = I * R - I = V / R - R = V / I .
How to decrease the flow rate without change the pressure ?
How to increase the flow rate without change the resistance ?
How to decrease the pressure without change the flow rate ?
The relationship between Current, Voltage and Resistance :
Examples ..
E3 : Find the current ?
Exercises ..
Exercises :
Q1 : A 3 V is applied across a 6 ohm resistor, what is the current ?
Q2 : lamp connected to a 6 V battery passes a current of 60 mA, what is the lamp's resistance ?
Q3 : A 1.2 k ohm resistor passes a current of 0.2 A, what is the voltage across it ?
Exercises :
A1 :
A2 :
A3 :
Summery
letters “E” or “V” .
letter “I” .
- Resistance measured in ohms, symbolized by the letter “R” .
- Ohm’s Law : V = I * R - I = V / R - R = V / I .
Any Questions ?
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