4A.3

Question 1

electrons movement throught a ciruit is caused by

Answer 1

an electric force or emf

Question 2

the electrical force is directly proportional to

Answer 2

the voltage which is proportional to the current

Question 3

what is resistance

Answer 3

the opposition of flow in an electrical current

Question 4

how can you calculate the resistance

Answer 4

resistance = potenial diffrence/ current

Question 5

what does a ohms law states

Answer 5

a current passing through a component is directly proportional to the voltage applied across it, provided that the temperature stays the same

Question 6

how to draw an I V filament bulb graph

Answer 6

look in page 157

Question 7

why does the line in the I V filament bulb graph curve

Answer 7

because at higher voltage a higher current passes through, causing an increase in temperature in the metal to increase its resistance as the ions are moving faster now

Question 8

how do you draw a diode graph

Answer 8

look page 157

Question 9

what can we tell from a diode I V graph

Answer 9

1. diode only conducts in the forward direction (so the current is zero for negative voltages)
2. it requires a minimum voltage called the threshold in order for it to start conducting

Question 10

in diode, the value of the threshold is usually around

Answer 10

0.6

Question 11

how do you draw a thermistor I V graph

Answer 11

page 157

Question 12

how does the I V thermistor graph look like that and why

Answer 12

as the voltage increase, the gradient of the curve increase and that is because more voltage means more currents which result in more temperature lowering the resistance since the thermistor is made from semiconducting materials whose atoms release more conduction electrons as the temperature increase