Advertisements
Advertisements
प्रश्न
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 .
Advertisements
उत्तर
R = 100 Ω
l = 5m
`A = 3 xx 10^-7 "m"^2`
`K = (rho l)/A` ⇒ `therefore rho = (RA)/l`
`δ = (100 xx 3 xx 10^-7)/5 = 60 xx 10^-7`
= `6 xx 10^-6 Omega-m`
APPEARS IN
संबंधित प्रश्न
Use the data in the Table given below to answer the following –
Which among iron and mercury is a better 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 | |
What is the general name of the substances having infinitely high electrical resistance?
How does the resistance of a conductor depend on:
length of the conductor?
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?
How does the resistance of a wire change when:
its material is changed to one whose resistivity is three times?
Plastic insulation surrounds a wire having diameter d and length l as shown above. A decrease in the resistance of the wire would be produced by an increase in the ______.
The resistance of a wire of 0.01 cm radius is 10 Ω. If the resistivity of the wire is 50 × 10-8 Ω, find the length of this wire.
How will the resistance of a wire be affected if its
- length is doubled, and
- radius is also doubled ?
Give justification for your answer.
