A bar of iron at is gently placed into of water at contained in a calorimeter

PHYSICS · Single correct · CBSE · Physics · Thermal Properties of Matter · Thermal Properties of Matter

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}

(b)

49^{\circ}\text{C}

(c)

33^{\circ}\text{C}

(d)

27^{\circ}\text{C}