Mass of the aluminium sphere (m1)= 0.047 kg
Initial temperature of the aluminium sphere=100oC
Final temperature= 20oC
Change in temperature (ΔT1)= 100oC−23oC=77oC
Let, specific heat capacity of Al =c1
Amount of heat lost by Al= m1×c1=ΔT1
= 0.047kg×c1×77oc
Mass of the water m2 =0.25 kg
Mass of the calorimeter m3=0.14kg
Initial temperature of water and calorimeter= 20oC
Final temperature= 23oC
Change in temperature (ΔT2)= 23oC−20oC=3oC
Specific heat capacity of water (c2)=4.18×103Jkg−1C−1
Total amount of heat gained by calorimeter and water
= m2×c2×ΔT2+m3×c3×ΔT2
=0.25×4.18×103×3oC+0.14×0.386×103×3o=3297.12J
At steady state, heat lost by Al= heat gained by water+ heat gained by calorimeter
Therefore 0.047kg×c1×77oc=3297.12J
∴c1=911.058Jkg−1c−1