Question

Calculate the resistance of copper wire of length 2m and area of cross section 10-6m2. Resistivity of copper is 1.7 x 10–8Ωm.

Answer 1

Answer:

0.034 ohms

Explanation:

Given:

$resistance = \rho \: \frac{l}{a}$

Length of the copper wire = 2 metres (l)

$Area \ \: of\ cross\ section\ of\ copper\ wire = 10 ^{ - 6} m ^{2}$

Resistivity of copper = 1.7×10^-8

To find:

• Resistance of the copper wire

Substituting the values:

$resistance = \frac{1.7 \times 10 ^{ - 8} \times 2 }{10 ^{ - 6} }$

$resistance = 1.7 \times 10^{ - 8} \times 2 \times 10^{6}$

$resistance = 3.4 \times 10 ^{ - 2}$

The resistance of the copper wire is equal to:

$\frac{3.4}{100}$

Resistance = 0.034 ohms

The resistance of the copper wire is equal to 0.034 ohms

Answer 2

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★Question

⋄ Calculate the resistance of copper wire of length 2m and area of cross section 10-6m2. Resistivity of copper is 1.7 x 10–8Ωm.

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Given:-

• Length of copper wire =2m
• Area of cross section =10^-6m²
• $resistivity \: of \: copper = 1.7 \times 10 {}^{ - 8} ohm$

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To find :-

⋄ Resistance of copper wire.

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$r = p \frac{l}{a} \\ \\ r = \frac{1.7 \times 10 {}^{ - 8 } \times 2 }{10 {}^{ - 6} } \\ \\ r = 3.4 \times 10 {}^{ - 2}$

∴The resistance of copper wire is 3.4×10^-2

=3.4/100=0.034 ohm.