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Ohm’s Law. Calculating Current, Voltage, and Resistance. SC Physical Science Standards. PS-6.6 Explain the relationships among voltage, resistance, and current in Ohm's law. PS-6.7 Use the formula V = IR to solve problems related to electric circuits. 3 Factors of Electricity.
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Ohm’s Law Calculating Current, Voltage, and Resistance
SC Physical Science Standards • PS-6.6 • Explain the relationships among voltage, resistance, and current in Ohm's law. • PS-6.7 • Use the formula V = IR to solve problems related to electric circuits.
3 Factors of Electricity Voltage Current Resistance
Voltage • Voltage Difference- the ‘push’ that causes charges to move • An electric charge haselectrical potential energy. • The closer one charge is to another, the more energy they have to push or pull on each other. • Measured in volts (V).
When a battery is connected, it is voltage that pushes and pulls the electrons through the wire to the other end of the battery.
Current The flow of electrons through a conductor. Measured in amperes or amps (a). Represented by I in the formula.
R E S I S T A N C E • When a material opposes the flow of electric charges. • This happens when electrons flowing through a wire run into things in the wire and bounce around. • Measured in Ohms (Ω). • Represented by R in the formula. • Things that affect resistance: • Type (what it is made of) • Temperature (increase temp, • increase motion) • Length (longer wire = further distance) • Thickness (diameter of the wire)
Measuring Voltage, Current, and Resistance • Volt-meter- device to measure voltage • Ammeter- device to measure • current • Ohm-meter- device to measure • resistance
Ohm's Law • Ohm’s Law states that the current in a circuit is directly proportional to the voltage in the circuit, and is inversely proportional to the resistance in the circuit. • If the voltage increases and resistance stays the same, current will increase. • If the voltage stays the same and the resistance increases, current will decrease. voltage Current = resistance
V R I Using Ohm's Law V=Voltage I=Current R=Resistance
Looking for voltage ? V = V I X R I = R Looking for resistance ? Looking for current ? V R = I Using Ohm's Law