what is the role of an ammeter?

and where is it positioned in a circuit?

measures current in a circuit

in line with the component - as the current needs to flow THROUGH them

what is the role of a voltmeter?

and where is it positioned in a circuit?

measures the difference in voltage between two points

is positioned on both sides of a component - or on another ‘branch’

in a series circuit, describe the features of:

a) current

b) potential difference

c) resistance

a) current - is equal across all components

b) total pd is equal to addition of all pds

c) res - of all components is different

in a parallel circuit, describe the features of:

a) current

b) potential difference

c) resistance

a) current - split between different branches NOT EQUAL

b) pd across all components are equal

c) res - of all components are different

in a symbol of a cell, which one is positive and which is negative?

long one = positive

short one = negative

what two factors does current depend on?

resistance

potential difference

what is the equation to calculate potential difference?(give units and full words)

V = IR

potential difference (V) = current (A) x resistance (Ω)

define potential difference

the difference in voltage between two points

what is the difference between a variable resistor and a normal resistor?

a variable resistor’s resistance can change, a normal resistor’s resistance cannot

how does a battery cause a current to flow in a circuit?

in a cell, the positive terminal is at a higher electric potential than the negative terminal.

and so there is a POTENTIAL DIFFERENCE in which the electrons move from the higher energy terminal to the other (to balance out)

what is the equation to calculate the energy transferred in a circuit?

J = V x Q

energy transferred (J) = potential difference (V) x charge (C)

state the factor which allows the transfer energy in a circuit

resistance

explain how a hotter wire affects the resistance

- in wire/component, ions usually vibrate up and down
- vibrating ions get more energy so they vibrate faster
- so more electrons collide with the ions

SO MORE RESISTANCE AS MORE ENERGY IS TRANSFERRED BY CURRENT