Physics

Problem

0.300\,\text{kg}

bar of iron at

250^{\circ}\text{C}

is gently placed into

0.500\,\text{kg}

of water at

20^{\circ}\text{C}

contained in a calorimeter. Before thermal equilibrium is reached,

8\%

of the thermal energy that leaves the iron is lost to the surroundings. Taking specific heats as

c_{\text{Fe}}=450\,\text{J}\,\text{kg}^{-1}\,^{\circ}\text{C}^{-1}

and

c_{\text{w}}=4186\,\text{J}\,\text{kg}^{-1}\,^{\circ}\text{C}^{-1}

, what is the final equilibrium temperature? a)

38^{\circ}\text{C}

49^{\circ}\text{C}

33^{\circ}\text{C}

27^{\circ}\text{C}