Two wires A and B with circular cross sections are made of the same metal and have equal lengths, but the resistance of wire A is three times greater than that of wire B. What is the ratio of the radius of A to that of B?

1.3
2.?3
3.1
4.1/?3
5.1/3


4

Physics & Space Science

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A hologram is simply a

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This visible-light photo shows a starburst galaxy. What is going on with the reddish gas that seems to be emerging on both sides of it?

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