[单选题]
The diagram shows the
7)f4yhxrk 0fu m9 n2) 4hufqpq equipoten
u1a6ka:yy -bk tial lines in a field due to A and B. What may be represented by A and B?
1 6-ayuaybk:k
I. 2 equal masses.
II. 2 equal charges of the same sign.
III. 2 equal charges of opposite sign
A. Only
B. and only
C. Only
D. ,, and
参考答案:
C
本题详细解析:
Explanation:
Equipotential lines are perpendicular to field lines, which means the field lines must be directed from A to B or vice versa. That is only possible for 2 charges with opposite sign. In I and II, the forces from the two objects would be in opposite directions, giving a resultant field zero at the midpoint, and equipotential lines of a “peanut” shape.