What can be the cause of fatigue of workers?

All of these

The correct answer is option 4- All of these.

There can be many causes for fatigue like long working hours, doing unsuitable work, having uncordial relations with the boss or bad working conditions etc. Such hindrances in good performance should be removed.

Fatigue study-  A person is bound to feel tired physically and mentally if she/he does not rest while working. The rest intervals will help one to regain stamina and work again with the same capacity. This will result in increased productivity. Fatigue study seeks to determine the amount and frequency of rest intervals in completing a task. For example, normally in a plant, work takes place in three shifts of eight hours each. Even in a single shift a worker has to be given some rest interval to take her/his lunch etc. If the work involves heavy manual labour then small pauses have to be frequently given to the worker so that she/he can recharge her/his energy level for optimum contribution. There can be many causes for fatigue like long working hours, doing unsuitable work, having uncordial relations with the boss or bad working conditions etc. Such hindrances in good performance should be removed.