The resistance of a copper wire 200 m long is 21 $$\Omega .$$ If its thickness (diameter) is 0.44 mm, its specific resistance is around
A. 1.2 x 10-8 $$\Omega $$-m
B. 1.4 x 10-8 $$\Omega $$-m
C. 1.6 x 10-8 $$\Omega $$-m
D. 1.8 x 10-8 $$\Omega $$-m
Answer: Option C
This Question Belongs to Electrical Engineering >> Current Electricity
Resistance of a material always decreases if
A. Temperature of material is decreased
B. Temperature of material is increased
C. Number of free electrons available becomes more
D. None of the above is correct
The minimum charge on an ion is
A. Equal to the atomic number of the atom
B. Equal to the charge of an electron
C. Equal to the charge of the number of electrons in an atom
D. Zero
Current velocity through a copper conductor is
A. the same as propagation velocity of electric energy
B. independent of current strength
C. of the order of a few micro m/s
D. nearly 3 x 108 m/s
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