In a charge-free region of space, a closed container is placed in an electric field. Which of the following is a requirement for the total electric flux through the surface of the container to be zero? (hw 2a.6)
A. The container must be oriented in a certain way.
B. The field must be uniform.
C. The container must be symmetric.
D. The requirement does not exist -the total electric flux is zero no matter what.

Beryl states that insulation with the smallest possible thermal conductivity is best to keep a house warm in winter, but worst for keeping a house cool in summer. sapphire insists the reverse is true: low thermal conductivity is good in the summer, but bad in the winter. which one, if either is correct? a. beryl, because low thermal conductivity results in low heat transfer. b. beryl, because low thermal conductivity results in high heat transfer. d. sapphire, because low thermal conductivity results in high heat transfer. e. neither, because low heat transfer is desirable both in summer and in winter.