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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 .
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`
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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 | |
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| Mercury | 94.0 × 10−8 | |
| Manganese | 1.84 × 10−6 | |
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