Answers

2014-12-07T20:23:37+05:30
A flask which does not allow radiation of heat so keeps a substance cool and does not allow a substance"s heat to escape and helps to make it hot.It ia a useful deviceAlso known as vaccum flask
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2014-12-07T20:54:39+05:30
A thermos flask has double walls, which are evacuated and the vacuum is silvered on the inside.
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