Electricity

Question 1

what is a field

Answer 1

Physical quantity that has a value for each point in space

Question 2

if a charge is positive what direction would the electric field point

Answer 2

away

Question 3

if a charge is negative what direction would the electric field point

Answer 3

towards

Question 4

for electrical potential energy what does it mean by conservative

Answer 4

only depends on start and end points not the distance travelled

Question 5

An insulator means what for the charges

Answer 5

cant move freely through
e.g. semipermeable membrane

Question 6

a conductor means what for the charges

Answer 6

able to move freely around
e.g. the inside or outside of the cell

Question 7

if outside the cell in 0mV and inside the cells is -85mV what is the change in potential energy from the inside to the outside.

Answer 7

0-(-85)
= 85mV

Question 8

if one cell has 0 on outside and -80mV in the inside
and another cell has +80mV on outside and 0 inside
what is the difference

Answer 8

No difference the both will be the same

Question 9

adding capacitors in series does what to the capacitors

Answer 9

1. reduces
2. makes smaller

Question 10

what type of charge does conventional current point in the direction for carriers need to flow

Answer 10

positive

Question 11

what is the equation for ohms law

Answer 11

V=IR

Question 12

what is the equation for resistance and resistivity

Answer 12

R= p (l/A)

Question 13

what are kirchhoff’s 2 laws

Answer 13

1. sum of potential charges around loop = 0
   current flowing into junction is the same as flowing out

Question 14

how do you calculate resistors in series

Answer 14

R1 + R2…

Question 15

how do you calculate resistors in parallel

Answer 15

1/ R1 + 1/R2….

Question 16

resistors in series what does it mean for the current flowing and potential difference

Answer 16

current flowing through all resistors is the same

potential difference across each resistor is the sum of the individual potential difference

Question 17

resistors in parallel what does this mean for potential difference and current flow

Answer 17

current flow: resistors in the sum of individual currents

potential difference: same

Question 18

what is the equation for power in electrical circuits

Answer 18

P=VI

Question 19

what is the equation for power in resistor

Answer 19

P= I^2R

Question 20

for AC what rule can be used

Answer 20

power

Question 21

if there are 2 lamps what will the current flow, brightness and how much power of each lamp will the lamps use

Answer 21

flow and voltage is half
brightness is dimmer
each lamb uses 1/4 power

Question 22

Capacitance of the membrane means

Answer 22

slow turn off and turn on

Question 23

what did benjamin franklin find for rubbing silk on glass will the glass what charge

Answer 23

positive

Question 24

the separation of charges in a neutral object is called what

Answer 24

polarisation

Question 25

the force between point charges is explained through what law

Answer 25

coulombs

Question 26

if two charges have the same sign what type of force is this

Answer 26

repulsive - e.g. like charges repel

Question 27

if there is more than one source charge then super position principle says you can do what

Answer 27

calculate the electric field due to each of the source charges individually and then sum the result

Question 28

conduction in metals is due to the movement of what charge electrons - what does this mean for the current in travels in what direction to the movement of elections

Answer 28

negative electrons current is in the opposite direction

Question 29

small cross sectional area and long length have largest/smallest resistance

Answer 29

largest resistance

Question 30

how do you calculate capacitors in series

Answer 30

1/C1+1/C2....

Question 31

how do you calculate capacitors in parallel

Answer 31

C1+ C2...