NIOS Class 10 Science Activity 16.3 Electrical Energy

This activity explains the verification of Ohm’s law through a simple experiment.

 

Electrical Energy Activity

This activity is based on the NIOS Class 10 science and technology (212) Chapter 16- Electrical Energy, Module 4.

Verification of Ohm’s Law

Aim

To establish the relationship between the current flowing through a conductor and the potential difference across its ends

Material Used

    1.  Dry cell (1.5 V)

    2.  Voltmeter

    3. Ammeter

   4. Fixed resistance coil (1 Ohm)

   5. Rheostat (0-1 Ohm)

   6. Plug key

   7. Connecting wires

Procedure

We connect a fixed resistor(R), an ammeter (A), a dry cell, a plug key(K), and a rheostat (Rh) in series, and connect a voltmeter (V) in parallel to the resistor.

When the key is open, the ammeter and voltmeter show  a zero reading. Now we insert the plug key into the key and adjust the rheostat so that both meters show readings.

We record these readings. We increase the current by sliding the rheostat and record the readings. We repeat this process 4-5 times.

Finally, we plot a graph of voltage (V) and current(I).

Observation

When the current is increased in the circuit, the potential difference across the ends of the resistors also increases. The graph between voltage and current is a straight line.

Explanation

The straight line in the graph shows that the ratio of potential difference and current is constant, and this constant is called the resistance of the conductor.

     V∝I

      V=RI

So, this experiment verifies Ohm’s law, which states that current through a conductor is directly proportional to the potential difference across the ends of the resistor when other physical conditions like temperature remain constant.

 

Conclusion

 This activity verifies Ohm’s law.

     

        V∝I

       `V=RI`

       `R=V/I`

 

The resistance of the conductor is a constant value.

 

Frequently Asked Questions

1. What does the straight line in the graph indicate?

Answer – The straight line in the V-I graph indicates that current is directly proportional to voltage and verifies Ohm’s law.

2. How is a voltmeter connected in an electric circuit?

Answer – The Voltmeter is connected in parallel in an electric circuit.

3. What is the use of an ammeter in an electric circuit?

Answer – An ammeter measures current flowing in the circuit.