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प्रश्न
State Ohm’s law and draw a neat labelled circuit diagram containing a battery, a key, a voltmeter, an ammeter, a rheostat and an unknown resistance to verify it.
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उत्तर
It states that electric current flowing through a metallic wire is directly proportional to the potential difference V across its ends provided its temperature remains the same. This is called Ohm's law.
V = IR
Experimental Verification: Reassemble the circuit according to the diagram. The circuit consists of a battery, an unknown resistance, a voltmeter with its positive terminal facing the battery's anode, and a rheostat and ammeter connected in series. With the key closed, and the rheostat set to zero, the ammeter and voltmeter should display the lowest possible readings. After that, the rheostat is adjusted step-by-step, and the values of A and V are recorded at each interval. The ratio of `"V"/"I"` is always found to be constant. This verifies Ohm's Law.
The temperature and other physical parameters of the conductor must be kept constant.
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संबंधित प्रश्न
Name the law which is illustrated by the above V−I graph.
The graph between V and I for a conductor is a straight line passing through the origin.
What should remain constant in a statement of this law?
A car bulb connected to a 12 volt battery draws 2 A current when glowing. What is the resistance of the filament of the bulb? Will the resistance be more same or less when the bulb is not glowing?
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.
A wire of resistance 3 ohm and length 10 cm is stretched to length 30 cm. Assuming that it has a uniform cross section, what will be its new resistance?
How does an increase in the temperature affect the specific resistance of a :
(i) Metal and
(ii) Semiconductor ?
State microscopic form of Ohm’s law.
What is ohmic device?
State Ohm’s law? How can it be verified experimentally? Does it hold good under all conditions? Comment.
The heat produced by a 100 w heater in 2 minute is equal to
