4. A 3.0-inch diameter titanium sphere at 0 °F is placed into a hot oil bath at 250 °F. (A) Can lumped capacitance be used to evaluate T(t)? (B) Regardless of your answer to (A), assume that lumped capacitance is valid and determine the temperature of the sphere 5 and 15 minutes after it is placed in the bath. (C) What is the maximum diameter titanium sphere where lumped capacitance can be used (i.e., Bi < 0.1)?

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