Currents In Electrical Circults

Question 1

What happend to certain insulated materials when they are rubbed togetehr?

Answer 1

They become electricaly charwged

negitively chaged electrons are rubbed off one material and onto another

Question 2

What happens to the insulated material which gains electrons?

Answer 2

It becomes negatively changed

Question 3

What happens to the insualted material which loses electron?

Answer 3

It is left with an equal positive charged

Question 4

What happens when 2 electrically charged objects are brought together?

Answer 4

They exert a force on each other

Question 5

Two objects that carry the same type of charge…

Answer 5

Repel

Question 6

Two objects that carry different charge…

Answer 6

Attract

Question 7

What are electrical charges allowed to do in certain substances, such as metals?

Answer 7

They can move easily

Question 8

What is an elecric current?

Answer 8

it is a flow of electric charges

Question 9

what is the size of the electric current?

Answer 9

It is the rate of flow of electric charges

Question 10

The equation for the size of the current is:
Q
I = — What do these symbos mean?
t

Answer 10

I = current in Amps
Q =charge in coulombs
t = time in seconds

Question 11

The equation for the potential differnce is:
W
V= — What do these symbos mean?
Q

Answer 11

V = pottential difference in volts
W = work done in joules
Q = charge in coulombs

Question 12

What are current-potential graphs used to show?

Answer 12

They are used to show how current through a component varies with the potential difference across it

Question 13

Who can the resistance of a component be found?

Answer 13

by measuring the current through, and potential difference across the resistor

Question 14

The equation for the resitance is:
V
R = — What do these symbos mean?
I

Answer 14

R = the resistace in ohms
V = pottential difference in volks
I = current in amps

Question 15

What does the current of a component depend on?

Answer 15

It depends on its resistane. the greater the resistanxe the smaller the currenet for a given potantial difference across the comnponent

Question 16

The potential difference provided by cells connected in series is the sum…

Answer 16

of the potential difference of each cell (depending on the direction in which they are connected)

Question 17

For components connected to a series circuit the total tesistance it the sum of…

Answer 17

The resistance of each component

Question 18

For components connected to a series circuit, the current is…

Answer 18

the same in each component

Question 19

For components connected to a series circuit, the total potential difference to the supply is…

Answer 19

shared between the components

Question 20

For components connected to a parallel circuit, the potential differnce across each component is…

Answer 20

the same

Question 21

For components connected to a parralel circuit the total current through the whole circuit id the sum of…

Answer 21

The current throuhg the seperate components

Question 22

The resistance in a filament bulb …… as the temperature …….

Answer 22

increases and increases

decreases and decreases

Question 23

The current through a diode flows in which direction?

Answer 23

only one

Question 24

What is the resistant of a diode in the revers direction?

Answer 24

very high

Question 25

When does resistance increase?

Answer 25

The length of the wire increases | The thickness of the wire decreases

Question 26

How is resistance caused?

Answer 26

An electric current flows when electrons move through a conductor, such as a metal wire. The moving electrons can collide with the ions in the metal. This makes it more difficult for the current to flow, and causes resistance.

Question 27

Why does the increase of the length of the wire cause as increase in resistance?

Answer 27

The resistance of a long wire is greater than the resistance of a short wire because electrons collide with ions more often.

Question 28

Why does a thinner cause a greater resistance?

Answer 28

The resistance of a thin wire is greater than the resistance of a thick wire because a thin wire has fewer electrons to carry the current.

Question 29

When does an LED emit light?

Answer 29

when a current flows thorugh it in the forwards direction

Question 30

Why is there an increase in the use of LEDs for light?

Answer 30

Because they use a much smaller current than other forms of lighting

Question 31

The resistance of a LDR decreases as light intensity.....

Answer 31

Increases

Question 32

The resisatance of a thermistor decreases as the temperature...

Answer 32

Increase