Question

State Ohm’s law. Write the necessary conditions for its validity. How is this law verified experimentally? What will be the nature of graph between potential difference and current for a conductor? Name the physical quantity that can be obtained from this Graph.

Answer 1

Answer:

.

Explanation:

1. Ohm's Law is a formula used to calculate the relationship between voltage, current and resistance in an electrical circuit. To students of electronics, Ohm's Law (E = IR) is as fundamentally important as Einstein's Relativity equation (E = mc²) is to physicists
2. The voltmeter (V) measures the potential difference across the ends of the resistance wire (R). As the key (K) is closed, current flows in the circuit. The rheostat (Rh) is adjusted to get the minimum (non-zero) reading in the ammeter (A) and voltmeter (V). The ammeter and voltmeter readings of current (I) are noted

Answer 2

Answer:

Ohm’s law : When the physical conditions such as temperature etc. remain same, the

current flowing through the conductor is directly proportional to the potential difference applied

across the ends of the conductor, i.e.,

I is directly proportional to V

V/I=CONSTANT

V=IR

Necessary condition for validity of Ohm’s law is that physical condition such as

temperature of the conductor remains same.

Procedure:

Experiment to verify ohm's law

Procedure : 1. Connect the various components as

2. Close the sky, so that current begins to flow in the circuit.

3. Note down the potential difference (V) across the conductor PQ of resistance R shown by the

voltmeter and the corresponding current (I) shown by the ammeter.

4. Now move the knob of rheostat so that the current in the circuit increases.

5. Again note down the potential difference (V) across the conductor R in the voltmeter and

current in the circuit shown by ammeter.

6. Repeat the experiment five times by increasing the current in the circuit by moving the knob of

the rheostat in steps.

The value of V/I = R (constant)

Plot a graph between V and I by taking V along X- axis along. We get a straight line passing

through origin.

Conclusion : From the graph between V and I, we conclude that I = V, which is Ohm's law.

Hence Ohm's law is verified experimentally.

Ohm's law does not hold under all conditions. Ohm's law does not hold for non-ohmic material

such as electrotyte