Fields D.2 Electromagnetic Fields & Potential (id: 6aa7c5129)

本题目来源于试卷: Fields D.2 Electromagnetic Fields & Potential，类别为 IB物理学

[单选题]
A positive charge Q and four points on equipotential lines bv;l/iax4 l6 r.y yp4qsu px,+ 4.zofsare represented snt8c2pfmfr0bxpjx9 :/ j47 t in the diagram s4m8jf 7jrt/ :0sxpp92c bxt fnhown.
A negative ion is moved from location 1 to 2, then to 3 and finally to 4. Which of the following gives the correct nature of the net work done on the ion during each section of this movement?

A. 1 to 2 is negative ; 2 to 3 is positive ; 3 to 4 is positive
B. 1 to 2 is positive ; 2 to 3 is negative ; 3 to 4 is negative
C. 1 to 2 is negative ; 2 to 3 is zero ; 3 to 4 is positive
D. 1 to 2 is positive ; 2 to 3 is zero ; 3 to 4 is negative


参考答案:  C


本题详细解析:

Explanation​:

The negative ion is attracted by the positive charge, therefore its energy at the inner equipotential line is less than the outer one.

Moving from 1 to 2, it moves to a lower energy, therefore work is negative

Moving from 2 to 3, it moves along the same equipotential line, therefore no work done

Moving from 3 to 4, it moves to a higher energy, therefore positive work is done.

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