electricity Flashcards
formula for resistance
resistance (Ω) = voltage (V) / current (A)
what does power tell us
power tells us the rate which an appliance transfers energy
What does the forumla Q=IT stand for?
Charge = Current * Time
power formula
power (W) = voltage (V) x curent (A)
What is an LDR? (Light dependant resistor)
An LDR is a resistor that changes resistance based on an amount of light
Dark conditions : high resistance
Light : low resistance
why do currents have a heating effect?
electrons move around the circuit, they collide with the ions that make up the wires and components. these collisions cause the electrons to lose kinetic energy. the kinetic energy is transferred to thermal energy, heating up the material.
What is a short circuit.
A circuit where electric current passes thorugh an unidentified, shorter pathway. This causes things such as:
Explosions called flash arcs
Melting components and starting fires
what happens if the current is higher than the fuse rating?
the wire melts which breaks the circuit
What is a parallel circuit?
A parrallel circuit is a circuit that has multiple branches that current can take. When the current meets a junction - it will split.
what is the voltage
the voltage tells us that whilst passing through the circuit how much energy has been gained or lost by each unit of charge
What is a live wire
The live wire carries the high voltage current from the mains supply to the appliance (or load). The voltage of this wire is 230V.
energy transfer in circuits formula
energy (J) = coulomb charge (C) x voltage (V)
Voltage of mains electricity?
230V
how does the resistance of an LDR change if the light changes?
low light intensity = low ldr
high light intensity = high ldr
Benefits of a parrallell circuit
When one stops working, the rest continue to work. This can be used in things such as light switches or smth
