Answer:
The heat flows from iron block to lead block then it flows from lead block to iron block until the temperature of three blocks are equal.
Explanation:
Given data
Temperature of the copper block = 20 °c
Temperature of the lead block = 30 °c
Temperature of the iron block = 70 °c
We know that according to law of thermodynamics heat always flows from higher temperature body to lower temperature body Until the temperature of all bodies becomes equal.
Therefore in the given problem the heat flows from iron block to lead block then it flows from lead block to iron block until the temperature of three blocks are equal.