• # question_answer 100 g of water is heated from Ignoring the slight expansion of the water, the change in its internal energy is (specific heat of water is 4184 J Kg/K) A) 4.2 kJ              B) 8.4 kJ  C) 84 kJ              D) 2.1 kJ

$\Delta Q=MS\Delta T=100\times {{10}^{-3}}\times 4184\times 20=8.4\times {{10}^{3}}$ $\Delta Q=84\,kJ$and $\Delta W=0$ $\Delta Q=\Delta U+\Delta W\Rightarrow \Delta U=8.4\,kJ$ Hence, the correction option is (b).