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प्रश्न
Name the electrical property of a material whose symbol is "omega".
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उत्तर
Resistance is represented by the symbol Omega, Ω. Resistance has the following electrical properties:
- The resistance of a conductor depends on its length. It is directly proportional to the length, R α L.
- The resistance of a conductor is inversely proportional to its area of cross-section, i.e. R α 1 / A.
- Resistance depends on the nature of the material of the conductor.
- Resistance also depends on the temperature of the conductor.
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संबंधित प्रश्न
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Sulphur, Silver, Copper, Cotton, Aluminium, Air, Nichrome, Graphite, Paper, porcelain, Mercury, Mica, Bakelite, Polythene, Manganin.
Distinguish between good conductors, resistors and insulators. Name two good conductors, two resistance and two insulators.
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How does the resistance of a conductor depend on:
area of cross-section of the conductor?
What would be the effect on the resistance of a metal wire of:
increasing its diameter?
What would be the effect on the resistance of a metal wire of:
increasing its temperature?
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Resistance of a metal wire of length 5 m is 100 Ω . If the area of cross - section of the wire is `3 × 10^-7 "m"^2` , Calculate the resistivity of the metal .
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Reason: They have free charge carriers.
Use the data in the Table given below to answer the following –
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Table give below Electrical resistivity of some substances at 20°C
| 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 | |
| Alloys |
Constantan (alloy of Cu and Ni) |
49 × 10−6 |
| Manganin (alloy of Cu, Mn and Ni) |
44 × 10−6 | |
| Nichrome (alloy of Ni, Cr, Mn and Fe) |
100 × 10−6 | |
| Insulators | Glass | 1010 − 1014 |
| Hard rubber | 1013 − 1016 | |
| Ebonite | 1015 − 1017 | |
| Diamond | 1012 − 1013 | |
| Paper (dry) | 1012 | |
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