Electric Circuits Flashcards
When is emf equal to potential difference (voltage)?
When no charges are flowing in the circuit
Important components of a circuit
Battery Conducting wire Switch Light bulb Resistor/rheostat Ammeter Voltmeter
What does a battery do?
Converts chemical energy into electrical energy
What does conducting wires do?
Allows the flow of charge from one terminal of the battery to the other/through the circuit.
Equation used for calculations with emf and potential difference
V = W/Q or W =VQ
W - energy transferred between two points
V - potential difference in volts
Q - Charge in coulomb
Series circuits
The total potential difference is equal to the sum of the potential differences across all individual components
Rs = R1 + R2 + R3
Parallel circuits
The total current in the circuit is equal to the sum of the branch currents
1/Rp = 1/R1 + 1/R2 + 1/R3
Unit of resistance
Symbol of resistance
Unit - One ohm (Ω) (is equal to one volt per ampere)
Symbol - R
Potential difference is measured in?
Volts (V)
Current strength is measured in?
Amperes (A)
Letter for current strength in an equation
Current strength = I
Direction of conventional current
Direction in which positive charges move in the circuit. From the positive terminal of the battery to the negative terminal.
Ammeter is connect in ____ and has ____ resistance
Connected in series
Low resistance
Voltmeter is connect in ____ and has ____ resistance
Connected in parallel
Very high resistance
Equation to calculate current strength
I = Q/t I - current in amperes (A) Q - charge in coulomb (C) t - time in seconds (s) Or I = V/R (Current strength = voltage / resistance)
Resistance is the ____ to flow of electric charges
Opposition
Factors that affect resistance
- Thickness of the conductor
- Length of the conductor
- Temperature of the conductor
(4. Type of material of the conductor)
Resistance equation
R = V/I (known as Ohm’s law)
Why does a battery go flat eventually?
All the chemical energy in the battery has been converted into electrical energy and has been transferred to the components of the circuit.
Lower resistance characteristics of the conductor
Thicker, shorter, colder conductor
High resistance characteristics of the conductor
Thinner, longer, warmer conductor
