A copper cable needs to carry a current of 200 A with a power loss of only 3.0 W/m. What is the required radius of the copper cable? (The resistivity of copper is 1.7 ´ 10-8 W×m.)
1) 0.21 cm
2) 0.85 cm
3) 3.2 cm
4) 4.0 cm
5) 4.7 cm
Answer: 2) 0.85 cm
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The "drive force" that pushes a car forward is
A) actually zero whenever the car has no acceleration. B) exerted by the road pushing forward against the tires. C) exerted by the road pushing upward against the tires. D) exerted by the engine pushing forward against the axle. E) exerted by the engine pushing backward against the axle.
In the figure below the blue object arrow is replaced by one that is much taller than the lens. How many rays from the object will strike the lens?
A parallel-plate capacitor has plates of area 0.80 m2 separated by a distance of 3.0 mm. What is this capacitor's capacitance?
A) 270 F B) 70 F C) 2.4 × 10-9 F D) 4.8 × 10-10 F E) 3.6 × 10-10 F
The total radiant power emitted by a blackbody is proportional to its _________________ raised to the fourth power
Fill in the blank(s) with correct word