A composite material is made of alternating thin lamellae of copper (resistivity 1.69x10^-6ohm-cm) and niobium-titanium alloy (resistivity 7x10^-5ohm-cm) of equal thickness.

What is the resistivity of this composite measured parallel to the lamellae? If current is passed through the composite in this direction, what fraction of the current will be carried by the copper? How will the electric fields of the two phases compare?

What is the resisitivity of this composite measured perpendicular to the lamellae? If current is passed through in this direction, what will be the ratio of the electric field in the alloy to that in the copper?

At a temperature of 4.2 K, the resistivity of the copper has decreased to 1x10^-8 ohm-cm, and the niobium-titanium alloy has become superconducting. Answer questions (a) and (b) for this situation.

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