Ice starts forming in a lake with water at 0∘C when the atmospheric temperature is −10∘C.If the time taken for the first 1 cm of ice to be formed is 7 hours, then the time taken for the thickness of ice to change from 1 cm to 2 cm is
Ice starts forming in lake with water at 0o C and when the atmospheric temperature is −10o C. If the time taken for 1 cm of ice to form is 7 hours, then the time taken for the thickness of ice to change from 1 cm to 2 cm is