A `10g` piece of iron `( C =0.45 J//g^(@)C )` at `100^(@)C` is dropped into `25g` of water `( C =4.2 J//g^(@)C)` at `27^(@)C`. Find temperature of the rion and water system at thermal equilibrium .

Options

A. `30^(@)C`
B. `33^(@)C`
C. `40^(@)C`
D. None of these

Answer

A

Explanation

Heat lost by iron + Heat gained by water = 0
`10 xx0.45 (T -373)+25xx4.2 xx(T-300)=0`
`" "T=303" K or " 30^(@)C`