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Question
How will you infer with the help of an experiment that the same current flows through every part of the circuit containing three resistances in series connected to a battery?
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Solution
Take three resistances R1, R2 and R3
- Connect them in series combination using battery, ammeter and key as shown in the diagram.
- First of all, connect the ammeter between battery and R1 and note down the reading.
- After that, connect the ammeter between R1 and R2 and note down the reading.
- After that, connect the ammeter between R3 and battery.
- Note down the reading of the ammeter in each steps.
It is observed that ammeter shows the same reading in all the three situations. This shows that same current flows through all the three resistors.
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| Electrical resistivity of some substances at 20°C | ||
| − | Material | Resistivity (Ω m) |
| Conductors |
Silver | 1.60 × 10−8 |
| Copper | 1.62 × 10−8 | |
| Aluminium | 2.63 × 10−8 | |
| Tungsten | 5.20 × 10−8 | |
| Nickel | 6.84 × 10−8 | |
| Iron | 10.0 × 10−8 | |
| Chromium | 12.9 × 10−8 | |
| Mercury | 94.0 × 10−8 | |
| Manganese | 1.84 × 10−6 | |
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49 × 10−6 |
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44 × 10−6 | |
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100 × 10−6 | |
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| Diamond | 1012 − 1013 | |
| Paper (dry) | 1012 | |
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