You might have heard of giving polio drops after specific duration to the children of specific age group , What do these polio drops contain ? Explain the concept behind it.

The water equivalent of a calorimeter is 10 g and it contains 50 g of water at 15^@C . Some amount of ice, initially -10^@C is dropped in it and half of the ice melts till equilibrium is reached. What was the initial amount of ice that was dropped (when specific heat of ice = 0.5 cal g^-1^@C^-1, specific heat of water = 1.0 cal g^1^@C^-1 and latent heat of melting of ice =80 cal g^-1 )?

A calorimeter of mass 50 gm and specific heat capacity 0.42 J g^-1 ^@C^-1 contains some water at 20^@ C. A metal piece of mass 20 gm at 100^@ C is dropped into the calorimeter. After stirring, the final temperature of the mixture is found to be 22^@C .Find the mass of water used. (specific heat of metal piece= 0.3 J g^-1 ^@C^-1 specific heat of water = 4.2 J g^-1 ^@C^-1 )

A calorimeter has mass 100 g and specific heat 0.1 kcal//kg^@C .It contains 250 gm of liquid at 30^@C having specific heat of 0.4 kcal//kg^@C . If we drop a Piece of ice mass 10 g at 0^@C , what will be the temperature of the mixture?

Give an account of Hershey and Chase experiment. What did it conclusively prove? If both DNA and proteins contained phosphorusand sulphur do you think the result would have been the same?