Electricity Flashcards
(26 cards)
what is electrical current?
current is the flow of electrical charge
how does the rate of flow of charge relate to current?
the greater the rate of flow of charge, the greater the current
What does it mean that the current has the same value at any point in a single closed loop?
it means that the current is constant throughout the circuit
what is the behavior of current through a diode?
the current flows in one direction only, with higher resistance in the reverse direction
how does current change with increasing current in a resistor
as current increases, electrons gain more energy and collide with atoms, increasing resistance.
how does temperature affect the resistance of a thermistor?
the resistance of a thermistor decreases at higher temperatures.
how does the length of a wire affect its resistance?
the greater the length of the wire, the more resistance it has.
What is the behavior of an LDR in different light conditions?
the resistance of an LDR decreases with greater light intensity and is highest in darkness
what is the function of a diode in a circuit?
a diode allows current to flow freely in one direction and has high resistance in the opposite direction
what is the total resistance in a series circuit?
the total resistance is the sum of the resistances of each component
how does current behave in a parallel circuit?
the total current into a junction equals the total current in each of the branches
what is the frequency and voltage of mains electricity in the UK?
the frequency is 50 Hz and the voltage is about 230 V
What is the difference between AC and DC current?
AC is alternating current that varies continuously, while DC is direct current that flows in one direction only
What are the three wires in a plug and their functions?
Live wire (brown, 230V), neutral wire (blue, 0V), and earth wire (green/yellow, 0V)
what is the purpose of the earth wire in a plug?
The earth wire is a safety wire that prevents the appliance from becoming live in case of a fault.
What is the formula for energy transferred in terms of power and time?
E = P x t
What is the national grid?
The national grid is a system of cables and transformers linking power stations to consumers across the UK
what is the function of transformers in the national grid?
Transformers change the potential difference for efficient power transfer
What do step-up transformers do?
Step-up transformers increase the potential difference from the power station to the National Grid
what do step-down transformers do?
Step-down transformers decrease the potential difference from the national grid to consumers for safety
what is the behavior of like and opposite charges?
Like charges repel each other, while opposite charges attract each other
What is the difference between insulators and conductors?
Insulators do not conduct electricity as the electrons are fixed, but conductors can carry electricity as their electrons are delocalized
What causes sparking in static electricity?
Sparking occurs when enough charge builds up and jumps through the air to balance out the charges.
How does the strength of the electrostatic force change with charge and distance?
The greater the charge, the greater the force, and the closer the objects are, the greater the force felt.
