Question

1meter length, 0.1millimeter radius ,1.59×10to the power of-8 specific resistance, then What is the Resistance?​

Answer 1

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Given, length of wire, l = 2m

cross sectional area , A = 10^-4 m²

Load , F = 102kgwt = 102 × 9.8 N

extension of wire, ∆l = 0.1cm = 0.001m

Longitudinal stress = F/A

= 102 × 9.8/(10^-4)

= 999.6 × 10^4 ≈ 1 × 10^7 N/m²

Longitudinal strain. = extension of wire/original length of wire = ∆l/l

= 10^-3/2 = 5 × 10^-4

we know, Young's modulus = longitudinal stress/longitudinal strain

= 1 × 10^7/5 × 10^-4

= 20 × 10^9 N/m²