PAG 04.1 Investigating Electrical Circuits

Question 1

How can you calculate the total resistance of a combination of resistors in series?

Answer 1

The total resistance equals the sum of the individual resistances

Question 2

How can you calculate the total resistance of a parallel combination of resistors?

Answer 2

The total resistance equals the inverse of the sum of the inverses of the individual resistances

Question 3

What device can be used to check the resistance of a component?

Answer 3

An ohmmeter or multimeter can be used to measure the resistance of a component

Question 4

How can the percentage of the total voltage across component be obtained?

Answer 4

A voltmeter can be used to measure the potential difference across the component. This can then be divided by the total voltage in the circuit and multiplied by 100%

Question 5

How should the total potential difference be shared across resistors in series?

Answer 5

The potential difference should be shared in the same ratio as the resistances of the resistors

Question 6

Why should the power-supply voltage be kept relatively low in this experiment?

Answer 6

The voltage should be kept low to reduce the heating effect of the components and to reduce the risk of electrocution

Question 7

Why should the voltmeters be calibrated before carrying out this experiment?

Answer 7

Calibrating the voltmeters reduces the risk of a systematic error in your data

Question 8

A 9ohm, a 6ohm and a 3ohm resistor are connected in parallel. What is their total resistance?

Answer 8

1/R=1/9+1/6+1/3
1/R=11/18
R=18/11