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प्रश्न
Which has more resistance:
a thick piece of nichrome wire or a thin piece?
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उत्तर
A thin piece of nichrome wire has more resistance because the resistance of a conductor is inversely proportional to its area of cross-section, i.e. R α 1 / A. The lesser the area of cross-section, the more the resistance.
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संबंधित प्रश्न
Two conducting wires of the same material and of equal lengths and equal diameters are first connected in series and then parallel in a circuit across the same potential difference. The ratio of heat produced in series and parallel combinations would be:
A copper wire has diameter 0.5 mm and resistivity of 1.6 × 10−8Ω m. What will be the length of this wire to make its resistance 10 Ω? How much does the resistance change if the diameter is doubled?
Why are copper and aluminium wires usually employed for electricity transmission?
List the factors on which the resistance of a conductor in the shape of a wire depends.
What is meant by conductors and insulators? Give two examples of conductors and two of insulators.
What is meant by the "resistance of a conductor" ? Write the relation between resistance, potential difference and current.
What happens to the resistance as the conductor is made thicker?
Which among iron and mercury is a better conductor of electricity?
A wire is 1.0 m long, 0.2 mm in diameter and has a resistance of 10 Ω. Calculate the resistivity of its material?
How does the resistance of a conductor depend on:
area of cross-section of the conductor?
How does the resistance of a conductor depend on:
temperature of the conductor?
What would be the effect on the resistance of a metal wire of:
increasing its length?
What would be the effect on the resistance of a metal wire of:
increasing its diameter?
How does the resistance of a wire change when:
its material is changed to one whose resistivity is three times?
The effective resistance between A and B is:
A cylindrical conductor of length l and uniform area of cross-section A has resistance R. Another conductor of length 2l and resistance R of the same material has an area of cross-section:
Use the data in the Table given below to answer the following –
Which material is the best conductor?
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 | |
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?
