required practical - current and potential difference

Question 1

what is current

Answer 1

the flow of charged particles

Question 2

what is potential difference

Answer 2

a measure of energy per unit transferred between two points in a circuit

Question 3

explain how you would investigate the current and voltage characteristics of circuit components

Answer 3

1. use the voltmeter to read the potential difference across the resistor
2. use the ammeter to read the current through the resistor
3. record these values in a table
4. adjust the variable resistor and record the new readings
5. do this several times to get multiple readings
6. now switch the direction of the potential difference by switching the direction of the battery (both meters should now have negative values) take several readings of potential difference and current
7. plot a graph

Question 4

what should the graph look like through a resistor and what would happen if the resistor is too hot

Answer 4

current through a resistor is directly proportional to potential difference

the graph shape would change

Question 5

what would the graph look like if a filament lamp was used and why `

Answer 5

”s” shape

this is because when the current increases the temperature of the lamp increases causing the resistance to increase

Question 6

what would you have to change about the circuit if a diode was used and why

Answer 6

need an extra resistor because diodes are very easily damaged to high current. because this current will be lowered (due to extra resistor) we need to use an extra sensitive ammeter.

Question 7

what would the graph look like if a diode was used and why

Answer 7

top of an “s”

only get a current when the potential difference is above 0.6 V
there will be no current if potential difference is reversed because a diode has high resistance in the reverse direction