Physics-
General
Easy
Question
A block of steel heated to 
is left in a room to cool. Which of the curves shown in figure represents the correct cooling behaviour?
- A
- B
- C
- D
The correct answer is: B
According to Newton’s law of cooling
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The only possibility of heat flow in a thermos flask is through its cork which is 75 cm2 in area and 5 cm thick. Its thermal conductivity is 0.0075 cal/cm secoC. The outside temperature is 40oC and latent heat of ice is 80 cal g–1. Time taken by 500 g of ice at 0oC in the flask to melt into water at 0oC is
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