# Use the data in Table 12.2 to answer the following – Table 12.2 Electrical resistivity of some substances at 20°C - Science

Short Note

Use the data in the Table given below to answer the following –
(a) Which among iron and mercury is a better conductor?
(b) Which material is the best conductor?
Table give below 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 Constantan(alloy of Cu and Ni) 49 × 10−6 Alloys Manganin(alloy of Cu, Mn and Ni) 44 × 10−6 Nichrome(alloy of Ni, Cr, Mn and Fe) 100 × 10−6 Glass 1010 − 1014 Insulators Hard rubber 1013 − 1016 Ebonite 1015 − 1017 Diamond 1012 − 1013 Paper (dry) 1012

#### Solution

(a) Resistivity of iron = 10.0 x 10-8 Ω
Resistivity of mercury = 94.0 x 10-8 Ω
Resistivity of mercury is more than that of iron. This implies that iron is a better conductor than mercury.

(b) It can be observed from Table given in the question that the resistivity of silver is the lowest among the listed materials. Hence, it is the best conductor.

Concept: Factors Affecting the Resistance of a Conductor
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#### APPEARS IN

NCERT Class 10 Science
Chapter 12 Electricity
Q 5 | Page 209