Question

A person has 20 m 60 cm long electric wire
and a water pipe of length 6 m, and he
requires 26 m of electric wire and 101 m long
2
water pipe. How much will he spend on buying
these if electric wire costs 25 per m and
water pipe costs 20 per m ?​

Answer 1

Step-by-step explanation:

l=0.1m=1000mm

d=0.2mm∴radius(r)=

2

0.2

=0.1mm

R=10Ω

To find,

Resistivity(ρ)

ρ=R

l

A

where,

R= Resistance

l= Length of wire

A= Cross sectional area of wire

Cross sectional area of cylinder (A)=Πr

2

⇒A=π×(0.1)

2

⇒A=0.0314mm

2

∴ρ=10(

1000

0.0341

)

⇒ρ=0.000314Ω−mm

⇒ρ≃3.14×10

−7

Ω−m

So, the resistivity of the material is equal to 3.14×10

−7

Ω−m

Hope it helps

Prutha