Question

The electrical resistivities of five substances A, B, C, D and E are given below A
5.20 × 10−8 Ω m
B
110 × 10−8 Ωm
C
2.60 × 10−8 Ωm
D
10.0 × 10−8 Ωm
E
1.70 × 10−8 Ωm
(a) Which substance is the best conductor of electricity? Why?
(b) Which one is a better conductor A or C? Why?
(c) Which substance would you advice to be used for making heating elements of electric iron? Why?
(d) Which two substances should be used for making electric wires? Why?

Answer 1

Answer:

1. E has lowest resistivity so it is best conductors

2. C is better conductor than A as its resistivity is less than A

3. B is best substance to make heating elements as its resistivity is very high so more heat will be produced

4. C and E has low resistivity so should be used to make electrical wires so that less loss takes place through heating

Answer 2

Explanation:

Given:

Material    Electrical resistivity

A         $5.20 \times 10^{-8} \Omega m$

B         $110 \times 10^{-8} \Omega m$

C         $2.60 \times 10^{-8} \Omega m$

D         $10.0 \times 10^{-8} \Omega m$

E         $1.70 \times 10^{-8} \Omega m$

So from the above table:

• (a) The substance which is the best conductor of electricity is E because the electrical resistivity is less and least resistivity designates good conductors.
• (b) The better conductor between A or C is C as the resistivity value of C is less than A and less resistivity designates good conductors.
• (c) I would advice to use substance B for making heating elements of electric iron because it possesses high electrical resistivity than others.
• (d) The two substances that should be used for making electric wires are C and E because both of them has less electrical resistivity as compared to others.