1. Aluminum plate of 0.05m diameter and thickness 0.01m is heated using coils by providing a supply of power 20W. Fix the value of chamber temperature at -20°C. Compare the value of its emissivity with black body at room temperature when same power is applied to it. (σ =5.67×10-8Wm-2K-4)
2. Calculate the value of emissivity of brass plate whose radius is 0.03m and thickness 0.03m at a chamber temperature of 50°C. Power supply of 33W is applied to both black plate and test plate.
3. What happens in the value of emissivity when initial power is increased from 33W to 48W supplied to iron plate? The diameter and thickness of iron plate is given as 0.1m and 0.05m and chamber temperature at 20°C.
4. A copper plate 0.04m in radius and thickness of 0.06m is heated with a supply of 65W.The temperature of the chamber is at 40°C.Calculate the emissivity of the plate.
5. How the diameter of the metal plate depends on the value of emissivity? If diameter of steel plate is increased from 0.05m to 0.1m, provided 84W power. The thickness of the plate is 0.08m and chamber temperature is at 80°C.