Ahollow sphere is constructed of pure aluminum with an inner diameter of 4 cm and an outer diameter of 8 cm. the sphere is covered with a 1-cm layer of insulating material having k = 50 w/m · k and the outside of the insulation exposed to h = 20 w/m2.k and t = 10c. the inside temperature of the sphere is maintained at 100c. (a) sketch the thermal resistance network and (b) determine the heat loss to the ambient.

When at a point two solid phase changes to one solid phase on cooling then it is known as a) eutectoid point b) eutectic point c) peritectic point d) peritectoid point

Consider a large isothermal enclosure that is maintained at a uniform temperature of 2000 k. calculate the emissive power of the radiation that emerges from a small aperture on the enclosure surface. what is the wavelength ? , below which 10% of the emission is concentrated? what is the wavelength ? 2 above which 10% of the emission is concentrated? determine the wavelength at which maximum spectral emissive power occurs. what is the irradiation incident on a small object placed inside the enclosure?

The characteristic roots of a dynamic system are: 1.7920 1.8160 i, -1.7920 1.8160 i, -0.4160 what is the order of this system? what are the settling time and damping ratio of the system?