chapter 2

Question 1

loosely bonded electrons

Answer 1

atttraction between positive nucleus has on those electrons are small.

Question 2

free elecrons experience an attraction to

Answer 2

neighbouring atoms

Question 3

elements with free electrons are classed as

Answer 3

good conductors.

Question 4

electron currrent flow

Answer 4

is from negative to posittive

Question 5

conventional current flow

Answer 5

positive to negative. used in heavy currents.

Question 6

conducter

Answer 6

substance through whic electric current can flow easily

Question 7

electric current

Answer 7

movement of electrons through a specific substance in a specific direction.

Question 8

potential difference

Answer 8

electricalpressure that causes current flow between twopoints in a circuit

Question 9

emf

Answer 9

device that has the ability to maintain pd between two points in a circuit is said to develop emf.

Question 10

devices that can develop emf

Answer 10

photo electric cell
electric cell or battery
electric generator
thermocouple

Question 11

resistance

Answer 11

opposition offerred to flow of electric current.

Question 12

resistor

Answer 12

device that has resistance as a chief property

Question 13

insulator

Answer 13

prevent the flow of electric current

Question 14

simple circuit needds the following:

Answer 14

.electric power device
.load such as a lamp
.two lengths of insulated conductors
.switch to open the continuous conducting path of circuit.

Question 15

heating effect of an electric current

Answer 15

when flow of current is restricted there will be heat generated. since there is no perfect conductor there will alays be heat generated from all parts of the circuit. can be putto usex stove heater etc

Question 16

power

Answer 16

it is the rate of doing work.

Question 17

power is measured in

Answer 17

watts

Question 18

where work is done energy is…

Answer 18

expanded

Question 19

power formula

Answer 19

v x I

Question 20

factors influencing the resistance of a conductor

Answer 20

.type of material {resistivity
.length of conductor in metres
.cross sectional area of conductor in m squared.
.tempersture of conductor.

Question 21

resistivity

Answer 21

theresisting power of a specific material.

Question 22

temperature coeeficccient of resistance

Answer 22

resistance of most materials are affected by changes in temperature.

Question 23

positive temp coefficcient of resistancce

Answer 23

resistance of most materials increases when temperature of that substance increases.

Question 24

negative temperature coeeficcient

Answer 24

resistance of of materials such as insulators pvc rubber , car batteries , carbon ddecreases with an increase in temperature.they are said to have a negative temperature coeffiecient of resistance.

Question 25

alloys low coefficient of resistance

Answer 25

ALLOYS{MIXTURE OF ELEMENTS} USED FOR THE RESISTANCE WIRE OF ELEMENTS HAVE EVRY LOW TEMPERATURE COEFFICIENT OF RESISTANCE. THE RESISTANCE VARIES SO LITTLE THAT TEMPERATURE CANBE NEGELGTED.

Question 26

3 EXAMPLES OF ALLOYS

Answer 26

EUREKA , MANGANIN , NICHROME

Question 27

SIMPLEST CONTRIBUTING FACTOR THAT DETERMINES THE INTERNAL RESISTANCE OF A CELL IS

Answer 27

THE MATERIAL IT IS MADE OUT OF.

Question 28

INTERRNAL REESISTANCE OF A CELL CAUSES INTERNAL

Answer 28

VOLT DROP WHILLE CURRENT IS FLOWING.

Question 29

INTERNL VOLT DROPAGE CAUSES

Answer 29

TERMINAL VOLTAGE DROP.

Question 30

when forming a battery , only

Answer 30

similar cells can be connected to form a battery

Question 31

cells may be grouped in

Answer 31

series , paralelle or series parallel combinations.

Question 32

since the emf of a single cell is low , they are often connected

Answer 32

in series.

Question 33

when cells are connected in series , it increases

Answer 33

emf and also the internal resistance.