A small slab of copper initially at a uniform temperature of is suddenly placed in…
PHYSICS · Multi-part · CBSE · Physics · Thermal Properties of Matter · Thermal Properties of Matter
Problem
A small slab of copper initially at a uniform temperature of 90∘C is suddenly placed in perfect thermal contact with a much larger slab of aluminum whose initial temperature is 20∘C. Assume that both slabs are solid and that no other energy exchanges (such as radiation to the environment) occur during the time interval considered.
(a) Describe, on the microscopic level of atomic collisions, the direction of energy transfer in the region near the interface immediately after contact is made. In your description, refer explicitly to the relative kinetic energies of atoms from each slab.
(b) Sketch or verbally describe how the distribution of atomic speeds for copper atoms
i. within 1nm of the interface
ii. for atoms several millimeters away from the interface in the interior of the copper slab
changes between t=0 and a short time Δt after contact. Explain the physical significance of the changes you describe.
(a) Describe, on the microscopic level of atomic collisions, the direction of energy transfer in the region near the interface immediately after contact is made. In your description, refer explicitly to the relative kinetic energies of atoms from each slab.
(b) Sketch or verbally describe how the distribution of atomic speeds for copper atoms
i. within 1nm of the interface
ii. for atoms several millimeters away from the interface in the interior of the copper slab
changes between t=0 and a short time Δt after contact. Explain the physical significance of the changes you describe.
(c) Explain why, after sufficient time has elapsed, the net rate of energy transfer across the interface becomes zero even though individual atomic collisions continue to occur. Identify the corresponding macroscopic observation.