Electrical Charge Transfer

Question 1

P.D definition

Answer 1

the amount of energy transferred from electrical to other forms of energy per unit charge

Question 2

resistance definition

Answer 2

the amount of opposition against current & equatioon

Question 3

coulomb definiiton

Answer 3

the charge in a current powered by 1V

Question 4

what happens to resistance in a parralel circuit

Answer 4

resistance decreases, due to increase in branches

Question 5

what is the definition of drift velocity

Answer 5

the average velocity of electrons when there is an APPLIED ELECTRIC FIELD

Question 6

number density units

Answer 6

m^-3

Question 7

what is conventional current

Answer 7

the flow of positive charge, from the positive terminal to the negative terminal

Question 8

electron flow definition

Answer 8

the flow of negative charge from the negative terminal to the positive terminal

Question 9

what does Kirchoff’s first law prove: conservation of…

Answer 9

conservation of charge

Question 10

definition of e.m.f

Answer 10

The energy transferred from chemical to electrical per unit charge

Question 11

definition of p.d

Answer 11

The energy transferred from electrical energy to other forms (e.g heat, light) per unit charge

Question 12

what does the gradient of a IV-characteristic graph represent?

Answer 12

1/resistance

Question 13

ohms law definition

Answer 13

p.d is directly proportional to current, assuming TEMPERATURE OF CONDUCTOR IS CONSTANT

Question 14

how is ohms law represented on a graph?

Answer 14

straight line which passes through origin

Question 15

name 3 ways to change resistance of a wire in a circuit

Answer 15

type of material, shape of wire, temperature of wire

Question 16

resistivity equation

Answer 16

resistance = (resistivity * length ) / area

Question 17

units for resistivity

Answer 17

ohm meters

Question 18

resistance defintiion

Answer 18

write R= I/V in words and say ‘ the amount of opposition against current’

Question 19

resistivity definition

Answer 19

write the equation & “a measure of how strongly a material opposes the flow of current”

Question 20

what is extraneous light (LDR section)

Answer 20

light from an exteral light source

Question 21

what happens to a NTC thermistor when there’s a rise in temperature?

Answer 21

releases more charge carriers, hence reducing the resistance. The increase in vibrations of particles has a lower impact on the resistance - net decrease in charge.

Question 22

what are the 2 things that could happen in a component that could impact its resistance when temperature increases

Answer 22

• increase in number of charge carriers - decrease resistance
• increase in vibrations (of positive ions) leads to more collisions - increasing resistance

Question 23

for a NTC thermistor, when temperature increases, resistance …

Answer 23

decreases

Question 24

for an LDR, when light intensity increases, resistance ….

Answer 24

decreases

Question 25

What does ‘e’ stand for

Answer 25

Elementary charge - charge on 1 electron

Question 26

what is Kirchoff's first law?

Answer 26

the sum of current entering a junction is equal to the sum of the current exiting it

Question 27

current definition

Answer 27

rate of flow of charge

Question 28

what is the charge of a single electron (e)? single proton?

Answer 28

electron: 1.6x10^-19 proton: 1.6x10^19

Question 29

number density definition

Answer 29

no. of free electrons per m^3 of a specific material

Question 30

what is an electron gun used fore?

Answer 30

A device that uses a large accelerating p.d to produce a narrow beam of electrons

Question 31

how do electron guns work

Answer 31

small metal filament is kept in a vacuum with a high p.d. (1) It is heated by electric current. (2) Some electrons gain enough K.E to escape metal and accelerate to anode. (3)

Question 32

light intensity units and equation?

Answer 32

lux; l is directly proportional to 1/distance^2`

Question 33

give a similarities between thermistor and LDR

Answer 33

when temp/ligth intensity increases, resistance decreases

Question 34

are thermistors and LDR's conductors, semi-conductors or insulators?

Answer 34

semi-conductors

Question 35

which of these has highest number density: insulators, semi-conductors, conductors

Answer 35

conductors

Question 36

what is the mass of an electron

Answer 36

9.11x10^-31

Question 37

true or false, thermistors and LDR's are ohmic conductors

Answer 37

false

Question 38

describe the structure of metal (in a wire)

Answer 38

a regular crystal structure of postive ions surrounded by a no. of free electrons

Question 39

what material is often used in computer processors and why?

Answer 39

silicon because it's a good semi-conductor

Question 40

conservation of charge definition

Answer 40

the net charge must be the same before and after an interaction; charge carriers can't be created or destroyed

Question 41

what does the gradient of an IV graph represent

Answer 41

1/resistance

Question 42

name 3 things that could impact resistance in a circuit

Answer 42

type of material, shape of material, temperature of wire

Question 43

IV characteristic of thermistor? of LDR?

Answer 43

search it up

Question 44

electronvolt defintiion

Answer 44

A unit of energy. (1) the energy transfered to or from an electron when it passes theough a p.d of 1 volt. 1eV = 1.6x10^-19J

Question 45

1eV is equal to ... J

Answer 45

1.6x10^-19J

Question 46

what is the equation of eV

Answer 46

eV=1/2mv^2

Question 47

what happens to electrons eneergy in electron gun/cathode ray tube when p.d increases

Answer 47

increase in energy = increase in speed of leectons

Question 48

what will happen to electrons speed in a cathode ray tube/ electron gun when there's no p.d?

Answer 48

speed of electron will be constant (not stationary)

Question 49

where does electron accelerate in cathode ray tube? where is the speed constant?

Answer 49

accelerates between anode and cathode | constant between anode and screen

Question 50

what are the advantages of using a data logger (4)

Answer 50

1) continuous record for a long time scale 2) records v.short time scale 3) automatic recording 4) data can be fed into computer for analysis