Question

silver wire has a diameter 0.4 mm and resistivity 1.6 into 10 raise to power minus 8 how much length of the wire is required to make 1 ohm coil

Answer 1

this may help u.......

Answer 2

Here we are given with :

Diameter of silver wire , D = 0.4 mm

Radius of wire = D/2 = 0.4 mm / 2 = 0.2 mm

= 0.2 × 10^-3 m

Resistivity = p = 1.6 × 10^-8 Ω-m

Resistance , R = 1 ohm = 1 Ω

Length is to be found .

Using the formula :

$R = p \frac{l}{A } = p \frac{l}{\pi {r}^{2} } \\ \\ l = \frac{\pi \: R\: {r}^{2} }{p} = \frac{22}{7} \times \frac{1 \times {(0.2 \times {10}^{ - 3} )}^{2} }{1.6 \times {10}^{8} } = 7.8 \: m$

The required length is 7.86 m .