chapter 15 : current electricity

Question 1

what is electric current ?

Answer 1

ELECTRIC CURRENT is produced when electrons move. Thus , an ELECTRIC CURRENT is formed by moving electrons .

Question 2

what is convectional current ?

Answer 2

CONVECTIONAL CURRENT is the movement of positive charges.

Question 3

what is electron flow ?

Answer 3

ELECTRON FLOW is the movement of electrons being repelled by the negatively charged terminal and attracted to the positively charged terminal.

Question 4

what is electric current and how to find it ?

Answer 4

ELECTRIC CURRENT is the rate of flow of electric charge.

I= Q/t
current (A) = charge (C) ➗ time (S)

Question 5

AN OPEN CIRCUIT

Answer 5

AN OPEN CIRCUIT can be caused by

~ an open switch
~ loose connections
~ missing/broken wires

Question 6

A SHORT CIRCUIT

Answer 6

A SHORT CIRCUIT is caused by

~ there is an alternative path with no resistance for current to flow through
• this leads to the current not flowing through the bulb .

Question 7

what is electromotive force ?

Answer 7

the ELECTROMOTIVE FORCE (emf ) of an electrical energy source is THE WORK DONE BY THE SOURCE IN DRIVING A UNIT CHARGE AROUND A COMPLETE CIRCUIT.

Question 8

how to measure electromotive force

Answer 8

E = W/Q

emf (v)= work done (J) ➗ charge (C)

Question 9

what is potential difference ?

Answer 9

POTENTIAL DIFFERENCE across a component in an electric circuit is THE WORK DONE TO DRIVE A UNIT CHARGE THROUGH THE COMPONENT.

Question 10

how to measure potential difference ?

Answer 10

V = W/Q

pd (V) = work done (J) ➗ charge (C)

Question 11

what is resistance ?

Answer 11

the RESISTANCE of a component is the RATIO OF THE POTENTIAL DIFFERENCE ACROSS IT TO THE CURRENT FLOWING THROUGH IT

Question 12

how to measure resistance

Answer 12

R = V/I

resistance (O) = potential difference (v) ➗current (A)