Current Electricity

Question 1

What is an electric current?

Answer 1

A flow of electric charge

Question 2

What is the unit and symbol for potential difference and how is it measured?

Answer 2

Volt
V
Voltmeter

Question 3

What is the unit and symbol for current and how is it measured?

Answer 3

Amp
A
Ammeter

Question 4

What is the unit and symbol for resistance and how is it measured?

Answer 4

Ohm
Omega symbol
Ohmeter

Question 5

What is the voltage, current, resistance triangle?

Answer 5

Very Crucial Rectangle

     Voltage Current x Resistance

Question 6

How do you measure the resistance of a coil?

Answer 6

1. Set a multimeter to act as an ohmmeter by changing the dial to the lowest resistance setting then switch it on
2. Connect the test leads to each end of the resistor and note the reading to get the resistance

Question 7

How do you measure potential difference and current and establish a relationship between potential difference, current and resistance?

Answer 7

1. Connect a power supply to a switch. Connect the switch to a coil in a beaker of cold water AND a voltmeter. Connect the other end of the coil to a voltmeter and an ammeter. Connect the ammeter to the power supply
2. Switch the power supply to the lowest setting and close the switch
3. Note the reading on the voltmeter and the ammeter.
4. Repeat the process at several other power supply settings and record results in a graph
5. The graph shows the current is proportional to voltage

Question 8

What are 3 everyday applications of the heating effect of a current?

Answer 8

Electric kettle, toaster, fuse

Question 9

What are 3 everyday applications of the magnetic effect of a current?

Answer 9

Loudspeakers, electric bells, circuit breakers

Question 10

What are 3 everyday applications of the chemical effect of an electric current?

Answer 10

Electrolysis, removal of hair, electroplating