22. NCERT Exemplar VII

1. Shopkeepers selling ice blocks usually cover them with jute sacks. Explain why.

 

Shopkeepers selling ice blocks usually cover them with jute sacks because materials like jute sacks, sawdust and newspapers acts as good conductorsinsulators and allowcannot allow escape or entry of heat through them.

 

2. To keep her soup warm Paheli wrapped the container in which it was kept with a woollen cloth. Can she apply the same method to keep a glass of cold drink cool? Give reason for your answer.

 

YesNo, Paheli cannot usecan use a woollen cloth to wrap around a glass cold drink to keep it cool because wool is a good conductorbad conductor of heat and doesn't letlet the heat transfer from the inner atmosphere to the outer atmosphere.