# E-PolyLearning

 11. Thermal diffusivity is given by a. A b. B c. C d. D

 12. At steady state the temperature variation in a plane wall, made of two different solids I & II is shown below. The thermal conductivity of material I a. is smaller than that of II. b. is greater than that of II. c. is equal to that of II. d. can be greater than or smaller than that of II.