At 20° C, 33 meters of copper wire has a resistance of 0.639 ohms. What is the
resistance of 165 meters?
Answers
Answer:
Aryan1500000X
Aryan1500000X
14.04.2020
Math
Secondary School
answered
1. Compute the resistance of a hardened copper rod 2 meters long and 8 mm
in diameter if the resistivity
of the material is 1.756 x 10-8 ohm-meters.
2. A 0.500-meter length of wire with a cross-sectional area of 3.14 x 10-6
meters squared is found to have
a resistance of 2.53 x 10-3
ohms. According to the resistivity chart, from what material is the wire
made?
3. The resistance of a uniform copper wire 50.0 meters long and 1.15 mm in
diameter is 0.830 ohms at
20° C. What is the resistivity of the copper at this temperature?
4. At 20° C, 33 meters of copper wire has a resistance of 0.639 ohms. What is
the resistance of 165
meters?
5. A 200 m long aluminum wire has the same resistance and cross-sectional
area as a carbon wire. What is
the length of the carbon wire?
6. A wire of radius R and length L has a resistance of 14 Ω. What is the
resistance of a wire made from
the same material that has twice the radius and five times the length?
Explanation:
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Given: At 20°C, the resistance of 33 meters of wire has a resistance of 0.639Ω
To find: Resistance of 165 meters
Solution: Resistance of copper wire is equal to, R = ρl/A
Where ρ is the resistivity of copper wire, l is the length of wire, and A is the area of cross-section of the wire.
Now, R₁ = ρ(33)/A
R₂ = ρ(165)/A
The resistivity of wire remains the same, and A will also be the same because the cross-section of wire does not change.
R₁/R₂ = 33/165
R₁/R₂ = 1/5
As given resistance of a wire of 33 meters is 0.639Ω.
Therefore, R₂ will be (0.639×5)Ω
R₂ = 3.195Ω
Therefore, the resistance of 0.639 meters of copper wire is 3.195Ω
- Resistance of the wire is directly proportional to the length of the wire and is inversely proportional to the area of cross-section.