Find the resistance (in mega) of a wire of length 20m, cross sectional area 1 cm2 and made of a material of resistivity 200m.
Find the resistance (in mega) of a wire of length 20m, cross sectional area 1 cm2 and made of a material of resistivity 200m.
A). 40
B). 4000
C). 80
D). 2000
2 answers
Solution:
Given:
Resistivity, ρ = 200 Ωm
Length, L = 20m
Cross sectional area, A = 1 cm² = 0.0001m²
Resistance, R = ?
We know that, R = ρ (L/A)
R = 200 Ωm(20m / 0.0001m²)
R = 200 Ωm(20m / 0.0001m²)
R = 4000 Ω / 0.0001
R = 40000000 = 4 × 10⁷
R = 40 × 10⁶
R = 40 Mega Ω
The correct option is 1). 40
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