Current pd and resistance

Question 1

What is current ?

Answer 1

The movement of charged particles

Question 2

Which way do particles move ?

Answer 2

Positive direction for an electrical current is the direction of movement of positive charge
In most cases negatively charged particles are the ones that move and they move in the opposite direction to the conventional current

Question 3

What is the charge for a proton ?

Answer 3

1.6*10^-19

Question 4

What is a coulomb ?

Answer 4

The charge passing a point when a current of one ampere flows for one second

Question 5

Ammeters:

Answer 5

Current is measured with an ammeter, it must be placed in series with the circuit an ammeter- negligible resistance so it does not affect the circuit in which it’s placed

Question 6

What is pd

Answer 6

The work done per unit charge V=W/Q

Question 7

Potential difference:

Answer 7

Charge only flows between two point if there is a pd between the two points
The work is the energy converted from electrical energy into other forms of energy
1 volt=1 joule per coulomb

Question 8

Voltmeters:

Answer 8

They measure the pd across a component and has to be placed in parallel with the pd being measured
Voltmeters have a very high resistance so no current flows through it and does not affect the circuit in which it is placed

Question 9

What is resistance ?

Answer 9

The ratio of pd across the component to the current flowing through it
Increase pd needed for current to flow this implies more resistance to the current flowing

Question 10

What is ohms law ?

Answer 10

For a metallic conductor at a constant temperature the current through the conductor is directly proportional to the pd across the wire
1 ohm= 1 volt ampere

Question 11

How is resistance measured ?

Answer 11

Resistance is measured by connecting an ohm meter across the component contains a power supply that sends a small current through the component size of current depends on the resistance