The convection coefficient for flow over a solid sphere may be determined by submerging the sphere, which is initially at 25 °c, into the flow, which is at 75 °c, and measuring its surface temperature at some time during the transient heating process. if the sphere has a diameter of 0.1 m, a thermal conductivity of 22 w/(m·k), and a thermal diffusivity of 0.40 ×10-5 m2/s, at what time will a surface temperature of 60 ºc be recorded if the convection coefficient is 300 w/(m2·k)?

The filament of an incandescent lamp has a temperature of 2000k. calculate the fraction of radiation emitted in the visible light band if the filament is approximated as blackbody

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?

Burgers vector is generally parallel to the dislocation line. a)-true b)-false