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填空题 A long solenoid is compressed to 80% of its original length (without changing the number of coils N), meanwhile the current on it changes from I to 2I. How does its magnetic energy change? 
From U to _______×U
学科：Physical Modelling A
时间：2023-06-05 08:10:54
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题目1单选题
Uniform magnetic field in cylindrical space changes as dB/dt = C > 0. If a straight wire and a curved wire are both placed in the changing field as shown in the figure, which one has a greater EMF in it? <img src="https://p.ananas.chaoxing.com/star3/origin/2c8d12f2f499bc31391be1dc96904cac.png">A. The straight wireB. All the 3 cases are possibleC. they have equal EMFD. the curved wire
题目2单选题
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题目3单选题
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题目4填空题
A long solenoid is compressed to 80% of its original length (without changing the number of coils N), meanwhile the current on it changes from I to 2I. How does its magnetic energy change? <img src="https://p.ananas.chaoxing.com/star3/origin/36ea9b909f2e36305227fd550c84375e.png"> From U to _______×U题目5填空题
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