A long, cylindrical, electrical heating element of diameter D=20 mm, thermal conductivity k=280 W/mK, density rho = 3000 kg/m3, and specific heat cp=1000 J/kgK is installed in a duct where air moves in cross flow over the heater at a temperature of 27oC and 10 m/s, respectively. Electrical energy is being dissipated from the heater at a rate of 1200 W/m. Determine the steady-state surface temperature of the heater. You may assume the air property values at T Infinity.

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?

Which from the following instrument is commonly used to detect the high pitch butzing sound in bearings? [clo4] a)-digital ultrasonic meter b)-infrared camera c)-spectroscopic d)-vibrometer

What is the chief metrological difference between measuring with a microscope and with an electronic comparator? a. the microscope is limited to small workpieces.a. the microscope is limited to small workpieces. c. the comparator can only examine one point on the workpiece. d. the microscope carries its own standard.