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Question
What are non-ohmic conductors? Give one exmaple. Draw a current-voltage graph for a non-ohmic conductor.
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Solution
The conductors which do not obey Ohm’s law (i.e., V/I is not constant) are called non-ohmic conductors.
Example: Diode valve.
The current-voltage graph for a non-ohmic conductor is shown in figure alongside.
RELATED QUESTIONS
What will be the change in the current if the potential difference is kept constant and the resistance of the circuit is made four times?
- It will remain unchanged.
- It will become four times.
- It will become one-fourth.
- It will become half.
Write the formula of resistivity
Name the law which is illustrated by the above V−I graph.
A resistance of 40 ohms and one of 60 ohms are arranged in series across 220 volt supply. Find the heat in joules produced by this combination of resistances in half a minute.
In an experiment of verification of Ohm’s law following observations are obtained.
|
Potential difference V (in volt) |
0.5 | 1.0 | 1.5 | 2.0 | 2.5 |
| current I (in ampere) | 0.2 | 0.4 | 0.6 | 0.8 | 1.0 |
Draw a V-I graph and use this graph to find:
- the potential difference V when the current I is 0.5 A,
- the current I when the potential difference V is 0.75 V,
- the resistance in a circuit.
Calculate the effective resistance across AB?
Obtain the macroscopic form of Ohm’s law from its microscopic form and discuss its limitation.
The temperature of a conductor is increased. The graph best showing the variation of its resistance is:
How is electric current related to the potential difference across the terminals of a conductor?
Draw a labelled circuit diagram to verify this relationship.
Why should an ammeter have low resistance?
