Electricity

Question 1

how do objects become charged?

Answer 1

if friction causes electrons to be transferred

Question 2

do like charges attract or repel?

Answer 2

repel

Question 3

what happens if there is a potential difference between two points?

Answer 3

the negatively charged electrons will move towards the positive side

Question 4

electrical current definition

Answer 4

the rate of flow of charge (how much charge flows through a point in the circuit in one second

Question 5

what are electrical currents measured in?

Answer 5

amps (A)

Question 6

what is the charge on an electron?

Answer 6

1.6 x 10^-19 coulombs

Question 7

what is a potential difference?

Answer 7

the work done per coulomb charge that passes between the parts

Question 8

what does a current need to flow?

Answer 8

potential difference

Question 9

what is potential difference measured in?

Answer 9

volts using a voltmeter

Question 10

what does a potential difference provide?

Answer 10

a push for the electrons (and current to flow)

Question 11

electrical current equation

Answer 11

charge = current x time or Q=I x T

Question 12

what is resistance

Answer 12

the opposition to the flow of charge

Question 13

what is resistance measured in?

Answer 13

ohms

Question 14

what is ohms law?

Answer 14

the current passing through a compound is directly proportional to the potential difference across it, provided the temperature is constant

Question 15

what is resistance

Answer 15

the opposition to the flow of charge

Question 16

what does increasing diameter do to resistance

Answer 16

decreases

Question 17

what does increasing conductivity do to resistance

Answer 17

decreases

Question 18

what does increasing length do to resistance

Answer 18

increases

Question 19

what does increasing temperature do to resistance

Answer 19

increases

Question 20

what does an iv graph show

Answer 20

the current passing through a component changes with potential difference

Question 21

what is the resistance of a fixed resistor

Answer 21

• constant

Question 22

what is the resistance of a filament bulb

Answer 22

increasing

Question 23

what is the resistance of a diode

Answer 23

very high so no current flow

Question 24

what is a series circuit

Answer 24

a circuit with only one loop

Question 25

rule for current in a series circuit

Answer 25

current is the same at all points. only one route for the current to flow around

Question 26

rule for potential difference in series circuit

Answer 26

shared between components , reduced by each resistance

Question 27

rule for total resistance of series circuits

Answer 27

equal to the sum of the resistance of each component

Question 28

problems with series circuits

Answer 28

if you remove a lightbulb or one burns out , they all go out

to have one bulb all the others must be on

Question 29

what is a parallel circuit

Answer 29

a circuit with multiple loops

Question 30

rule for total current in parallel circuits

Answer 30

total current is the sum of the currents through each branch

Question 31

potential difference rule in parallel circuits

Answer 31

pd across each component is the same as the supply voltage

Question 32

resistance rule in parallel circuits

Answer 32

total resistance is less than the resistance of the resistor with the least resistance

Question 33

what affects resistance in an ldr

Answer 33

light intensity

Question 34

where are ldrs useful

Answer 34

in circuits where light level drops below. a certain value so a light can be triggered to turn on

Question 35

what is the bird rule for ldrs

Answer 35

brightness increases resistance decreases

Question 36

what affects resistance in a thermistor

Answer 36

temperature

Question 37

what can thermistors be used in

Answer 37

circuits to regulate temperature

Question 38

what is the turd rule for thermistors

Answer 38

temperature up resistance down