3. One of these is a possible electrostatic field. Which one? (A)E = k[xyx̂ + 2yzŷ + 3xzẑ] (B)E = k[y²x̂ + (2xy + z²)ŷ + 2yzẑ] (C)E = k[yx̂ + x²ẑ] (D)E = k[yzx̂ + y²ŷ + z²ẑ]

8. A square loop of wire, of side a, lies midway between two long wires, 3a apart, and in the same plane. (Actually, the long wires are sides of a large rectangular loop, but the short ends are so far away that they can be neglected.) A clockwise current I in the square loop is gradually increasing: dI/dt = k (a constant). Find the emf induced in the big loop. Which way will the induced current flow? (A)μ₀ka ln2/π, counterclockwise (B)μ₀ka ln2/π, clockwise (C)μ₀ka ln2/(2π), counterclockwise (D)μ₀ka ln2/(2π), clockwise

3. One of these is a possible electrostatic field. Which one?
(A)E = k[xyx̂ + 2yzŷ + 3xzẑ]
(B)E = k[y²x̂ + (2xy + z²)ŷ + 2yzẑ]
(C)E = k[yx̂ + x²ẑ]
(D)E = k[yzx̂ + y²ŷ + z²ẑ]

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