24. Electric Force & Field; Gauss' Law

Draw the field lines for a pair of identical, positive charges.

(II) Draw, approximately, the electric field lines emanating from a uniformly charged straight wire whose length ℓ is not great. The spacing between lines near the wire should be much less than ℓ . [Hint: Also consider points very far from the wire up to 4ℓ .]

Draw, approximately, the electric field lines about two point charges, +Q and -3Q, which are a distance ℓ apart.

You’ve hung two very large sheets of plastic facing each other with distance d between them, as shown in FIGURE EX23.19. By rubbing them with wool and silk, you’ve managed to give one sheet a uniform surface charge density η1=−η0 and the other a uniform surface charge density η2=+3η0 . What are the electric field vectors at points 1, 2, and 3? <IMAGE>

FIGURE EX24.1 shows two cross sections of two infinitely long coaxial cylinders. The inner cylinder has a positive charge, the outer cylinder has an equal negative charge. Draw this figure on your paper, then draw electric field vectors showing the shape of the electric field. <IMAGE>