A gun fires a lead bullet of temperature 300 K into a wooden block. The bullet having melting temperature of 600 K penetrates into the block and melts down. If the total heat required for the process is 625 J, then the mass of the bullet is ______ grams. (Latent heat of fusion of lead $=2.5 imes10^4\,\mathrm{J\,kg^{-1}}$ and specific heat capacity of lead $=125\,\mathrm{J\,kg^{-1}K^{-1}}$)

Question

A gun fires a lead bullet of temperature 300 K into a wooden block. The bullet having melting temperature of 600 K penetrates into the block and melts down. If the total heat required for the process is 625 J, then the mass of the bullet is ______ grams. (Latent heat of fusion of lead $=2.5	imes10^4\,\mathrm{J\,kg^{-1}}$ and specific heat capacity of lead $=125\,\mathrm{J\,kg^{-1}K^{-1}}$)

Dr. Abubacker · Accepted Answer

[Solution by Dr. Abubacker] $Q=m\left(c\Delta T+Light)=m(125	imes300+2.5	imes10^4)=62500\,m=625\Rightarrow m=0.01$ kg $=10$ g. Answer (1).

Explanation

Reviewed by Dr. Abubacker

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