Which of the following electric fields could exist in a finite region of space that contains no charges? (in these expressions, A is a constant, and i, j, and k are unit vectors pointing in the x, y, and z directions, respectively.)
A. A(2xyi − xzk)
B. A(−xyj + xzk)
C. A(xzi + xzj)
D. Axyz(i + j)
E. Axyzi
(GR8677 #80)
Solution:
Gauss’ Law for no charges:
Use method of elimination:
(A). FALSE
A(2xyi − xzk)
→
(B). TRUE
A(−xyj + xzk)
→
Answer: B
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