As performed in the real lab:
Material required :
A resistor of about 5 Ω, an ammeter ( 0 - 3 A), a voltmeter (0 - 10 V), four dry cells of 1.5 V each with a cell holder (or a battery eliminator), a plug key, connecting wires, and a piece of sand paper.
- All the electrical connections must be neat and tight.
- Voltmeter and Ammeter must be of proper range.
- The key should be inserted only while taking readings.
- 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.
- Range of the given ammeter=.................... A.
- Least count of the given ammeter = ..................... A.
- Range of the given voltmeter = .....................V.
- Least count of the given voltmeter = .....................V.
- Mean value of V/I from observations, R = .......... Ω.
Observation from graph:
- Slope of I vs V graph = ...........
- R from graph = 1/ slope = .............. Ω.
As performed in the simulator:
- Click on Show Label checkbox to label/unlable the apparatus in the circuit.
- Click on Show Help checkbox to show/hide the 'help' for performing the lab.
- Click on the Observation Table tab below to open the Observation table.
- Drag the plug key to switch on/off the current.
- Adjust the rheostat such that ammeter shows the low value of Current (I). Note corresponding voltmeter reading.
- Increase the current by adjusting the slider of the rheostat and take about 5 or 6 sets of readings.
- Note carefully ammeter and voltmeter readings in each set and record in the Observation Table.
- Note V/I ratio for each set of reading in the Resistance column.
- Click on Plot Graph button to plot voltmeter readings (V) along the x-axis and the corresponding ammeter readings (I) along the y-axis in the graph.