本题目来源于试卷: Electric Currents，类别为 IB物理学
[问答题]
When you turn on a water-a:s*gzy )uygo j e/n:tl);dz1t+ba5nb/a zsp b,a5v faucet, the water usually flows immediately. You don’t have to wait for water to flow from the faucet valve to the spout. Why not? Is the same 5zp1 aa bnba+,tb s/v5thing true when you connect a wire to the terminals of a battery?
参考答案: Water flows immediately from the
spout because there is already water in the spout when you turn on the
faucet. Since water is (essentially)
incompressible, a push on the water from some distant location (at the valve or
pump) causes all the water to move almost immediately, pushing the water out of
the spout. In a battery, a similar
phenomenon exists in that the wires are “full” of charges (free
electrons). The voltage “push” from the
battery pushes all the electrons along the wire almost immediately, and the
first ones at the other end of the wire are the beginnings of the electric
current.
本题详细解析:
暂无
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