Question

Calculate the resistance of a 2m long nichrome wire of radius 0.321mm. Resistivity of nichrome is 15 x 10-6 Ω m. If the potential difference of 10v is applied across this wire, what.will be the current in the wire?

Answer 1

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Answer 2

"The current in the wire is 0.108 Ampere.

Given:

Resistivity of Nichrome$=\rho=15 \times 10^{-6} \Omega m$

Potential difference = 10 v

Length = 2m

Radius$=0.321 \mathrm{mm}=0.321 \times 10^{-3}$

Solution:

Area of cross section, $A=\pi r^{2}$

$A=\pi\left(0.321 \times 10^{-3}\right)^{2}$

$\Rightarrow A=3.24 \times 10^{-7}$

On using, the given below resistance formula, we get,

$R=\rho \frac{l}{A}$

$=15 \times 10^{-6}\left(\frac{2}{3.24 \times 10^{-7}}\right)$

$R=92.6 \Omega$

On using, ohm law, we can get the value of current, as current is a ratio of potential difference and resistance.

$I=\frac{V}{R}=\frac{10}{92.6}$

$\Rightarrow I=0.108 A$"