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Resistivity of a piece of wire calculation?
In this question, you will calculate the resistivity of a piece of wire.
When a potential difference of 12 V is applied to a wire 7 m long and 0.35 mm in diameter the result is an electric current of 2.3 A .
What is the resistivity of the wire ?
Express your answer using two significant figures, in units of Ω m (Ohm metres).
2 Answers
- ?Lv 75 years ago
R = rho*L/A
rho = R*A/L
R (resistance) = 12/2.3 ohms
L (length) = 7 metres
A (area) = (1/4)*pi*(0.35*10^-3)^2 square metres
(The area of cross-sectional area in square metres of a circular wire with diameter 0.35 mm)
Plug those numbers into the formula and use your calculator.
- 5 years ago
v=ir so r=12/2.3=5.21ohms now we know that r=(rho)L/A
calculate a=3.14*(.35*10^3/2)^2.
putting the values we get resistivity=r*a/l=.0715ohm metres.
