# P3.2 - Flashcards Preview

## OCR GCSE P1-P5 > P3.2 - > Flashcards

Flashcards in P3.2 - Deck (13)
1
Q

what is the role of an ammeter?

and where is it positioned in a circuit?

A

measures current in a circuit

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

2
Q

what is the role of a voltmeter?

and where is it positioned in a circuit?

A

measures the difference in voltage between two points

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

3
Q

in a series circuit, describe the features of:

a) current
b) potential difference
c) resistance

A

a) current - is equal across all components
b) total pd is equal to addition of all pds
c) res - of all components is different

4
Q

in a parallel circuit, describe the features of:

a) current
b) potential difference
c) resistance

A

a) current - split between different branches NOT EQUAL
b) pd across all components are equal
c) res - of all components are different

5
Q

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

A

long one = positive

short one = negative

6
Q

what two factors does current depend on?

A

resistance

potential difference

7
Q

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

A

V = IR

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

8
Q

define potential difference

A

the difference in voltage between two points

9
Q

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

A

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

10
Q

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

A

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)

11
Q

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

A

J = V x Q

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

12
Q

state the factor which allows the transfer energy in a circuit

A

resistance

13
Q

explain how a hotter wire affects the resistance

A
• 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