Answer:
It is because some of the heat is lost in the surroundings.
Step-by-step explanation:
To calculate the specific heat of the metal, the following steps are performed.
Take a piece of metal whose mass and the initial temperature is known.
Now take a beaker filled with some measured amount of water and the temperature of water is known.
Drop the heated metal piece in the water so that the equilibrium is reached.
According to the principle of calorimetery,
Heat lost by the metal = heat gained by the water
here, some of the heat is lost in the surroundings so we don't get the correct value of the specific heta of the metal.