Question

A) An engineer is designing a product in which a copper wire will carry large amounts of electricity. The resistive heating of a 66 g copper wire is expected to add 520 J of heat energy during a 10-minute operating cycle.

What is the temperature increase of the wire?

You may use the following information about copper to answer the question:

specific heat = 0.385 J g^-1 °C^-1

density = 8.94 g/cm³

coefficient thermal expansion = 6.5 µm m^-1 K^-1

^B)

An engineer is designing a product in which a copper wire will carry large amounts of electricity. The resistive heating of a 66 g copper wire is expected to add 520 J of heat energy during a 10-minute operating cycle.

What is the initial length of the wire, assuming it is a cylinder and its radius is 0.08 cm?

You may use the following information about copper to answer the question:

specific heat = 0.385 J g^-1 °C^-1

density = 8.94 g/cm³

coefficient thermal expansion = 6.5 µm m^-1 K^-1

^C)

An engineer is designing a product in which a copper wire will carry large amounts of electricity. The resistive heating of a 66 g copper wire is expected to add 520 J of heat energy during a 10-minute operating cycle.

By what percentage does the volume increase because of the temperature increase?

(Note: Remember to always use unrounded values in calculations then round final answers to the correct significant figures.)

You may use the following information about copper to answer the question:

specific heat = 0.385 J g^-1 °C^-1

density = 8.94 g/cm³

coefficient thermal expansion = 6.5 µm m^-1 K^-

^D)

Do you think the engineer should be considering this expansion in the design?

You may use the following information about copper to answer the question:

specific heat = 0.385 J g^-1 °C^-1

density = 8.94 g/cm³

coefficient thermal expansion = 6.5 µm m^-1 K^-1

Answer 1

(D) Since the expansion represents a very small percent increase in total length wire, then it should not have a significant impact in the design process