Explain why : (a) A body with large reflectivity is a poor emitter. (b) A brass tumbler feels much colder then a wooden tray on a chilly day. (c ) an optical pyrometer (for measuring high temperatures) calibrated for an ideal black body correct value for the temperature when the same piece is in the furnace. (d) The earth without its atmosphere would be inshospitably cold. (e ) Heating system based on circulation of steam are more effecient in warming a building than those based on circulation of hot water.