Experiments

 
1: Measuring Current and Potential Difference.   

 Part 1
Ammeter in series 
 

  1. Connect the power supply, load component and ammeter in series, as shown above. see circuit diagram
  2. Check that it all works.Does changing the position of the ammeter in the circuit change its reading?
Part 2. 
Ammeter in series, Voltmeter in parallel 
 
     
  1. Connect the voltmeter across the load in parallel see circuit diagram
  2. Measure the potential difference across the light bulb with the switch open, and then with it closed. record your results in a table .
  3. Now move the voltmeter leads from the light bulb to the terminals of the power supply, and repeat step 2.What readings do you get? Are they the same as the first reading.
  4. Now move the voltmeter leads to the terminals of the switch, and repeat step 2. Record your readings.
  5. Discuss your results with your teacher.
Potential Difference in Volts 
Position of meter Switch on Switch off
Across bulb
v
v
Across battery
v
v
Across switch
v
v
What reading do you think you would get at step 2 if there were two identical bulbs in the circuit?
 2: Measuring Resistance.    
  1. Set up the same circuit you had in experiment 1.
  2. Record the voltage drop cross the light bulb, and the current flowing through it.
  3. Add a second light bulb to the circuit. This will decrease the amount of current flowing in the circuit.
  4. Repeat step 2.
  5. Add a third light bulb, and repeat step 2.
  6. Copy your results into a table like the one below, or start a speadsheet program like Excel and graph the potential difference of the bulb vs the current flowing through it. Is the bulb an ohmic conductor?
  7. Test as many different resistors as you can.
 
 
Volts Supplied Current in circuit (A) Potential difference across bulb(v) Potential difference/Current
. . . .
You can also practice calculating Potential Difference, Current and resistance by   
 
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