The walls of flask are separated by vacuum and made of glass which is a poor conductor of heat.

The glass walls themselves have shiny surfaces.

The surface of inner wall radiates good amount of heat and the surface of outer wall absorbs some of the heat that is radiated from the inner wall.

The cork supports are poor conductors of heat.

huge black star which has zero acceleration due to gravity on its surface.

star which has moderate acceleration due to gravity on its surface.

star which has collapsed into itself and has large acceleration due to gravity on its surface.

star which has collapsed into itself and has zero acceleration due to gravity on its surface.

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