The resistance of a copper wire 200 m long is 21 Q. If its thickness (diameter) is 0.44 mm, its specific resistance is around_______________?
Correct answer: C. 1.6 x 10″"8 Q-m
- A. 1.2 x 10~8 Q-m
- B. 1.4 x 10~8 Q-m
- C. 1.6 x 10″"8 Q-m
- D. 1.8 x 10″8 Q-m
Explanation
Using ρ = RA/L and A = πd²/4, the cross-sectional area is about 1.52 × 10⁻⁷ m², giving ρ ≈ 1.6 × 10⁻⁸ Ω·m. This agrees with the known resistivity range of copper.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
Practise Circuit Analysis
394 free Circuit Analysis MCQs from Electrical Engineering, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Electrical Engineering questions like this
Electrical Engineering is on 2 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Circuit Analysis questions
In a circuit a 33 Q resistor carries a current of 2 A. The voltage across the resistor is
A light bulb draws 300 mA when the voltage across it is 240 V. The resistance of the light bulb is___________?
The resistance of a parallel circuit consisting of two branches is 12 ohms. If the resistance of one branch is 18 ohms, what is the resistance of the other ?
With rise in temperature the resistance of pure metals______________?
The resistance of a conductor varies inversely as___________?
Conductance is reciprocal of____________?