JEE MAIN - Physics (2022 - 29th June Morning Shift - No. 22)
The variation of applied potential and current flowing through a given wire is shown in figure. The length of wire is 31.4 cm. The diameter of wire is measured as 2.4 cm. The resistivity of the given wire is measured as x $$\times$$ 10$$-$$3 $$\Omega$$ cm. The value of x is ____________. [Take $$\pi$$ = 3.14]
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תְשׁוּבָה
144
הֶסבֵּר
Resistance $$ = \tan 45^\circ = 1\,\Omega $$
$$ \Rightarrow 1 = {{pI} \over A}$$
$$ \Rightarrow p = {{\pi {{(1.2\,cm)}^2}} \over {31.4\,cm}} = 1.44 \times {10^{ - 1}}$$ $$\Omega$$ cm
$$ \Rightarrow x = 144$$