A certain metal wire has a cross-sectional area of 1.0 cm2 and a resistivity of 1.7 × 10-8 Ω ∙ m. How long would it have to be to have a resistance of 1.0 Ω?

L=5882.35 m

Explanation:

Given that

Area ,A= 1 cm²

Resistivity  ,ρ = 1.7 x 10⁻⁸ Ω ∙ m

Resistance ,R= 1 Ω

Lets take length of the wire = L

Resistivity  =ρ

Resistance =R

Area =A

Resistance =R

Now by putting the values in the above equation get

L=5882.35 m

Therefore the length of the wire will be 5882.35 m.

if the thermos has a vacuum innner, then heat through conv currents and conduction are reduced = vacuum flask