Electricity Flashcards
what do fuses do
fuses stop the flow of current
how do fuses stop the flow of current
by melting the current to high
what do circuit breakers do
circuit breakers break the circuit if the current is to high
what does insulation and double insulation do
prevents people from touching exposed wires and getting shocked
what does earthing do
earthing provides a low resistance path to the ground. Earthing is mainly used to prevent an electric shock
why a current in a resistor results in the electrical
transfer of energy and an increase in temperature, and how?
resistors slow down the movement of electrons in the current, so the KE that was moving them is transferred into heat energy.
This can be used for various domestics contexts: e.g hair dryer, heaters
what is the equation for power
power = current x voltage
what is the equation of energy transferred?
energy transferred = current x voltage x time
what is an AC?
AC stands for alternative current. It is a typical electrical current, in which the direction of the flow of electrons switches back and forth.
It is used to deliver power to houses, office buildings, etc.
what is DC?
DC stands for direct current. It is an electrical current that flows in one direction. It is produced from a battery and used in some sensitive components
give 2 advantages on using a paralleled circuit
- -> allows additional components
- -> if one breaks, current can still flow through the other parts of the circuit
give 2 advantages of a series circuit
→ fewer wires, cheaper and easier to assemble.
→ uses less power.
why does the current in a series circuit depend on the applied voltage, number and nature of other components?
- as the voltage increases, the current also increases.
- in general, the more components in a circuit, the lower the current.
how does a current vary with wire?
with wire the current is directly proportional to the voltage (because the temperature is constant)
how does a current vary with resistors?
the current flowing will be the exact same as it was before the resistor. The current will become smaller though (the resistor reduces the current)
how does a current vary with metal filament lamps?
since the temperature ins’t constant in a filament lamp, the resistance increases dramatically as the current increases (because the lamp gets too hot in order to give out light)
how does a current vary with diode?
it will only allow the current to flow in one direction, as it has high resistance the other way.
(remember to look at picture on google docs.)
what is the effect of increasing resistance of a current in a circuit?
by increasing the resistance it decreases the current.
how do you increase the resistance of a current in a circuit?
by adding more components with higher resistance.
what is the effect of decreasing resistance of a current in a circuit?
by decreasing the resistance it will increase the current.
how do you decrease the resistance of a current in a circuit?
by replacing components of higher resistance with lower resistance ones.
what is the resistance of LDRs with illumination?
as illumination increases, resistance decreases
what does LDR stand for?
light-dependent resistors
what is the resistance for thermistors with temperature?
as temperature increases, resistance decreases
how do you check if there is a current in a circuit?
by adding a lamp or LEDs. If the current is flowing, the lamp will start glowing (hahhahah that rhymed… i think i have been studying too much… by the way the word is supposed to be “light up” but i thought “glowing” would sound cooler)
what is the formula for the relationship between voltage, current and
resistance
voltage = current × resistance
V = I × R
what is the rate flow of charge?
current
what is the formula for the relationship between charge, current and
time?
charge = current × time
Q = I × t
what is the electric current in solid metallic conductors?
a flow of negatively charged electrons. The electrons are free to flow in a metal to carry change.
what does a junction current look like?
A junction current splits to take both paths, they soon come back together when the paths meet again.
what is the voltage like when it is across two components connected in a parallel?
the voltage is the same
what is voltage?
it is the pressure from an electrical circuit’s power source that pushes charged electrons (the current) through a conducting loop. This enables them to do things such as light up a light bulb.
how is voltage measured like?
in volts
what is the formula for the relationship between energy transferred,
charge and voltage
energy transferred = charge × voltage
E = Q × V
what happens in a current when the voltage increases?
the current also increases
the more components in a circuit…
the lower the current.
