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1 a27 °C.

b123 K.

2The student is not correct. Internal energy includes the random kinetic energy of the molecules, and that is determined only by temperature. The velocity of the plane does not affect the random kinetic energy of the molecules. The internal energies of the two containers are the same.

3Above 50 °C. The high specific heat capacity of Y implies its temperature will not change by much.

4Steam will release its enormous latent heat of vaporization as it condenses into water.

5The one with the largest value of Δ T L (the middle diagram)

6It will stay the same. Doubling the area doubles the emitted power, but the vertical axis measures the spectral intensity B, which is power per unit area per unit wavelength so B will not change.