What are the differences between refraction and diffraction?

When applying kirchhoff's rules, one of the essential steps is to mark each resistor with plus and minus signs to label how the electric potential changes from one end of the resistor to the other. the circuit in the drawing contains four resistors, each marked with the associated plus and minus signs. however, one resistor is marked incorrectly. which one is it?

Acar drives toward the right over the top of a hill, as shown below. which arrow represents the centripetal acceleration? w x y z

Which is special about a dc circuit ? a. it has both series and parallel components b. it has only series or only parallel components c. charge moves in a single direction d. charge moves back and forth quickly