Problem Sheet 6

The numbers in square brackets refer to the number of the problem in your textbook.

1. [E12.2] If a bimetallic strip in an actuator has a thickness of 2mm and average thermal diffusivity a of 0.00005 per degree Celsius, how long will it take to respond when the temperature suddenly changes?
2. [E12.3] If the density of a new alloy is 7380 kg/m³, give an estimate of its specific heat.
3. [E12.4] Consider the alloy of the previous problem. If its melting point is 1540 K, estimate its thermal expansion coefficient.
4. [E12.6] If a ceramic coffee mug gets too hot to hold about 10 seconds after pouring in the hot coffee, and if the wall thickness of the cup is 2mm, what approximately is the thermal diffusivity of the cup? What approximately is the thermal conductivity of the cup material? If the cup were made of a metal with a thermal diffusivity of 2 x 10^6-5^^ m²/s, how long could you hold it?