Question

3. A copper wire has a diameter 0.5 mm and resistivity 1.6 x 10-8 m.
(1) What will be the length of this wire to make the resistance of 12 ?
(12) How much will be the resistance of another copper wire of same length but half the diameter


Its urgent please answer​

Answer 1

Answer:

R=10 Ω

ρ=1.6 x 10^(-8) Ω⋅m

d=0.05 mm

=0.05 x 10^(-3) m

=5 x 10^(-5)m

So r = 2.5 x 10^(-5) m

l=? m

now using,

R=ρl/A,

or R=ρl/π(r^2)

10= {[1.6 x 10^(-8)] x l}/ π x [(2.5 x 10^(-5)) ^2]

10= {[1.6 x 10^(-8)] x l}/[2 x 10^(-9)]

now find the value of l

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