circuits and currents

Question 1

whats an electrical circuit?

Answer 1

it is a closed loop that allows electrons to flow through it

Question 2

in a current, what do electrons do?

Answer 2

electrons move through the circuit, and their movement is what creates electric currents

Question 3

how do the electrons allow the electricity to work?

Answer 3

because an electron carries a negative charge (-1)

Question 4

an electric circuit could be considered a path for what?

Answer 4

for electric charges to flow along

Question 5

what are the 4 things needed for a path for the electrical charge to flow along?

Answer 5

1. a complete loop
2. a component (any device connected into a circuit e.g a bulb)
3. a source of energy (e.g a cell or a battery)
4. no short circuits (when an electric current skips over components, therefore there is too much current flow, as there is no resistance, and can cause wires to overheat, fire hazards, etc)

Question 6

what are conductors?

Answer 6

conductors are materials that allow the flow of electric charge

Question 7

what are really good conductors? why?

Answer 7

• metals
• because there are a lot of delocalised electrons that can move easily through the metal

Question 8

what are insulators?

Answer 8

insulators are materials that do not allow the flow of electric charge

Question 9

what are really good insulators? why?

Answer 9

• plastics
• plastics don’t have delocalised electrons to carry a charge

Question 10

why are insulators needed? (2)

Answer 10

1. to stop electric shocks by covering wires
2. to prevent short circuits, through keeping wires separated

Question 11

when do short circuits happen?

Answer 11

when 2 wires that carry currents touch each other directly

Question 12

how do metals carry a current?

Answer 12

• it is the delocalised electrons involved in metallic bonding that allow metals to conduct electricity
• the delocalised electrons are free to flow through the metal and so carry a current

Question 13

are ionic solutions able to conduct electricity? if so why?

Answer 13

ionic solutions are able to conduct electricity as they have mobile charge-carrying particles

Question 14

what is an ionic solution?

Answer 14

it is a liquid that contains dissolved ions, usually made by dissolving an ionic compound (e.g salt) in water

Question 15

what do series circuits have?

Answer 15

series circuits have only one path for charge to flow around

Question 16

what do parallel circuits have?

Answer 16

parallel circuits have more than one path around which the charge can flow

Question 17

whats a current?

Answer 17

measure of the flow of electrons around the circuit

Question 18

what is the symbol of a current?

Answer 18

I

Question 19

whats the potential difference?

Answer 19

it is the force driving the flow of electrons

Question 20

what is the symbol of the potential difference?

Answer 20

V

Question 21

whats the resistance?

Answer 21

everything that resists or opposes the flow of electrons

Question 22

what is the units of resistance?

Answer 22

Ohms (Ω)

Question 23

what is the symbol of resistance?

Answer 23

R

Question 24

what is the units of potential difference?

Answer 24

Voltage (volts)

Question 25

what is the units of the current?

Answer 25

Amperes (Amps)

Question 26

how does the current flow in a circuit? (direction-wise)

Answer 26

current always flows from the positive to negative