An electrically heated plate 15cm high and 10cm wide is maintained at 140°C. Estimate the rate of heat dissipation from both sides of the plate in an atmospheric at 20° C, if the radiation heat transfer co-efficient is 8.72W /m² -K. For air at the mean temperature of 80°C; Take kinematic viscosity= 21.09x10 m² /s, Pr 0.692, and k = 0.0305 W/m-K.

A 200mm diameter spherical steel ball initially at 500°C is rapidly immersed in an oil bath that is at 20°C. The convection coefficient is h = 600W/m²-K, and the steel ball has the following properties: c= 500J/kg-K, p= 7000kg/m³, k=30W/m-K. Determine the time taken (min) for temperature at the surface of the ball to drop to 100°C.

A mercury-in-glass thermometer having a diameter of 6 mm is placed in a verti- cal position to measure the air temperature in a metal warehouse in the summer. The walls of the warehouse are at 50°C. The convection coefficient is 7 W/m² - °C, and the emissivity of the thermometer may be taken as € = 0.9. Calculate the temperature indicated by the thermometer if the air temperature is 32°C.

In the arctic sea, the ice sheets are melting. Let's calculate the temperautre distribution in one such ice sheet. The sheet is 2 m thick. Under the sheet there is ice-water mixture and it can be assumed that the temperature of the bottom surface of the ice sheet is approximately 0°C. Air at -20°C is blowing above the sheet. The convection coefficient of air is 15 W/m².K. The thermal conductivity of ice is 2.2 W/m.K. What is the temperautre of icesheet at its center (i.e., at 1 m from the surface)?