Question

Draw a labelled diagram of experiment explaining Ohm's Law.

Answer 1

Experimental verification of Ohm's law

Procedure :

• Draw the circuit diagram as shown above.
  
• Arrange the apparatus as per the circuit diagram.
  
• Clean the ends of the connecting wires with sand paper and make them shiny.
  
• Make the connections as per circuit diagram. All connections must be neat and tight. Take care to connect the ammeter and voltmeter with their correct polarity. (+ve to +ve and -ve to -ve).
  
• Determine the zero error and least count of the ammeter and voltmeter and record them.
  
• Adjust the rheostat to pass a low current.
  
• Insert the key K and slide the rheostat contact to see whether the ammeter and voltmeter are showing deflections properly.
  
• Adjust the rheostat to get a small deflection in ammeter and voltmeter.
  
• Record the readings of the ammeter and voltmeter.
  
• Take atleast six sets of readings by adjusting the rheostat gradually.
  
• Plot a graph with V along x-axis and I along y-axis.
  
• The graph will be a straight line which verifies Ohm's law.
  
• Determine the slope of the V-I graph. The reciprocal of the slope gives resistance of the wire.