P4- Electric Circuits Flashcards
What is the force between two charged objects?
Non-contact force
What is the equation for charge flow?
Q = i x t
Charge flow (c) = current (a) x Time (s)
What does a circuit diagram show?
How components are connected together
What does a battery consist of
Two or more cells connected together
What is the size of an electric current?
The rate of flow charge
What is the equation of potential difference for resistance?
V = IR
P.d. Volts (v). Current (A) resistance ohms
What is the equation for potential difference across a component?
Potential difference across a component,
V volts v = energy transferred, E (joules, j)/ charge Q (coulombs, C)
What is the equation for the resistance of an appliance?
Resistance, R (ohms) = potential difference,V volts / current l amperes A
A filament lamps resistance increases if the …
Filaments temperature increases
In a diode how high and low is the forward and reverse resistance
Forward low
Reverse high
What happens to a thermistors resistance if it’s temperature increases
It decreases
What happens to the LDR’s resistance if the light intensity in it increases
Decreases
What is an electric current? And the unit?
A flow of electric charge around a circuit
Ampere (A) can be shortened to amp
How do you measure the current in a circuit
By using an ammeter
How do you measure potential difference?
Using a voltmeter
What is potential difference
A potential difference of 1 volt means that 1 joule of energy is transferred for each coulomb to f charge moving through the circuit
What is the total resistance of two resistors in parallel less than
The resistance of the smallest individual resistor
What do step up and step down transformers do?
Step up transformers increase the potential difference. This reduces energy loss in the transmission cables.
Step down transformers reduce the potential difference before the electricity to passes to homes
What are sockets and plug cases made of?
Stiff plastic materials that enclose the electrical connections. Plastic is used because it is a good electrical insulator.
What is the equation for power in terms of energy transferred?
Power P (watts, W) = energy transferred, E (joules, J) / time, t seconds, s
