The final temperature of the water after dropping the iron ball has been 60.
The heat transferred by the iron ball can be given by:
Heat (Q) = mcT
Q = heat transferred = 8.4 kJ
Q = 8400 J
m = mass = 200 g
c = specific heat = 4.2 J/g.
T = change in tempertaure = Initial temperature - final temperature
T = Final temperature - 50
8400 J = 200 g 4.2 J/g. (Final temperature - 50 )
Final temperature = 60.
The final temperature of the water after dropping the iron ball has been 60.