Figure CP27.74 shows a wire that is made of two equaldiameter segments with conductivities Ï 1 and

Figure CP27.74 shows a wire that is made of two equaldiameter segments with conductivities σ₁and σ₂. When current I passes through the wire, a thin layer of charge appears at the boundary between the segments.

a. Find an expression for the surface charge density η on the boundary. Give your result in terms of I, σ₁, σ₂, and the wire€™s cross-section area A.
b. A 1.0-mm-diameter wire made of copper and iron segments carries a 5.0 A current. How much charge accumulates at the boundary between the segments?

Transcribed Image Text:

→I Surface charge density ŋ FIGURE CP27.74