Industrial Revolution and Child Labor are interrelated in a strong way. This is not the fact that Child Labor did not exist before the advent of Industrial Revolution. But, actually in the time of Industrial Revolution, the extent of use of Child Labor increased tremendously.
This happened because, the factory owners preferred child laborers even more than the adult laborers. When Industrial Revolution came, different types of power driven machines started being used in the factories. These Industrial Machines did note require much strength to be operated. So, the Child Laborers were able to generate almost same productivity as of the adult laborers. But, the Child Laborers were paid very Low Wages compared to Adult Laborers. So, the Child Laborers became the obvious choice of the factory owners.
At those times, there were no laws for protecting child laborers. So, child laborers were exploited tremendously. They were compelled to work in very Poor Working Environment for long hours and in return they used to receive wages which were much lower than the adult laborers.
At one point the situation worsened by such extent, that voices started to rise in the society against the children's plight. Government tried to make Child Labor Laws to limit the use of Child Labor in the industries. But all the Factory Owners were against it. They were not ready to lose their Source of Cheap Labor. They were to trying to prove their point that they were actually helping the poor children by giving them money so that they can have food and avoid starvation.
The first general law against the use of Child Labor was successfully passed in 1833 and 1844. According to these laws, children below nine years of age were not allowed to work . The Children between 9 and 18 years of age were not allowed to work at night and not for more than twelve years in the day. These laws reduced the use of Child Labor but it was totally wiped out only after 20th century.