topic 2 -year 11 Flashcards
what is electric current
a flow of electric charge
what kind of circuit will electric charge flow through
a complete circuit if there is a potential difference
what is needed to make a current flow
a source of potential difference
what is the unit of current
ampere, A
what is potential difference
a driving force that pushes the charge round
what is the unit of potential difference
volts, v
what is resistance
anything that slows the flow of electric charge down
what does the current flowing through a component depend on
the potential difference across it and the resistance of the component
the greater the resistance across a component …
the smaller the current that flows (for a given potential difference across the component.)
what is the size of the current
the rate of the flow of charge
what does the ammeter measure
the current in amps flowing through the test wire
how must the ammeter be placed when investigating
in series with whatever your investigating with
what does the voltmeter measure
the potential difference across the test wire in volts
how must the voltmeter be placed when investigating
in parallel around whatever your investigating
what happens if we close the switch of a circuit
then electrons flow out of the cell and move around the circuit- which is called the electric current `
how do electrons move in cells
from the negative end of the cell to the positive end of the cell
what are the electrons carrying from the cell
energy
what do the electrons pass the energy to in the circuit
the pass it to the components such as the lamp
in the lamp of a circuit how is energy transferred
to light energy and thermal energy
how much energy are electrons carrying when they return to the positive end of the cell
they are carrying less energy than when they left the negative end
how can we measure the current in a circuit
by using an ammeter
describe the current in a series circuit
it is same all the way around
describe the current in parallel circuits
the current in the branches adds up to the total current leaving the cell
electric charge is measured in
C
a current of 1 ampere =
1 coulomb of charge flowing per second
describe the potential difference in parallel circuits
it is the same across each component
