A sphere and a cube of equal volumes both are made of iron and have similar surface. If both are cool in identical surrounding, at a lower temperature, then the ratio of the initial rates of loss of heat is

A sphere and a cube both made of copper have equal volumes and are blackened. These are heated to same temperature and are allowed to cool under same surroundings. The ratio of their rates of loss of heat is

Two solid spheres of radii R_(1) and R_(2) are made of the same material and have similar surfaces. These are raised to the same temperature and then allowed to cool under identical conditions. The ratio of their initial rates of loss of heat are

Two solid spheres of radii R_(1) and R_(2) are made of the same material and have similar surfaces. These are raised to the same temperature and then allowed to cool under identical conditions. The ratio of their initial rates of loss of heat are

Two solid spheres of radii R_(1) and R_(2) are made of the same material and have similar surfaces. These are raised to the same temperature and then allowed to cool under identical conditions. The ratio of their initial rates of loss of heat are

Two spheres made of same material have their radii in the ratio 1 : 3. They are heated lo the same temperature and kept in the same cool surroundings at a moderate temperature. Show that the ratio of their initial rates off all of temperature is 3 : 1 if the bodies are cooled by natural convection and radiation

A sphere and a cube of same material and same total surface area are placed in the same evaculated space turn by turn after they are heated to the same temperature. Find the ratio of their initial rates of cooling in the enclosure.