I've got homework assignment for 6 hours later but I could not even start to solve the problems below. I've done lots of research but I could not understand which equation must be used for each question.(adsbygoogle = window.adsbygoogle || []).push({});

1. Compare the thermal velocity with the drift velocity of electrons in a divalent metal wire carrying 7 A at 40 K. The wire has a diameter of 1mm. With the numbers that youâ€™ve calculated, describe the motion of the electrons in a few sentences.

2. What is the electrostatic force on the oxygen atom in a water molecule? Please use an

oversimplified model with each atom having an apparent charge equal to its valence.

Remember that this is not a linear molecule.

3. A composite material is made of alternating thin lamellae of copper (resistivity 1.69 x 10^-6 ohm-cm) and a niobium-titanium alloy (resistivity 7 x 10^-5 ohm-cm) of equal thickness. (a) 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 in the two phases compare? (b) What is the resistivity 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? (c) At a temperature of 4.2 K, the resistivity of the copper has decreased to 1 x 10^-8 ohm-cm, and the niobium-titanium alloy has become uperconducting. Answer questions (a) and (b) for this situation.

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# Homework Help: Materials science class homework

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