This is a question that is similar to questioning whether you will have any difficulties in getting to work and arriving to work on time. The interviewer may very well ask you this question if they are considering hiring you for the job, so you should expect to receive this question and be prepared to answer it in an effective manner. Keep in mind when answering this question that you should take care regarding any questions that ask about the number of hours per week that you will be able to work so that you do not accidentally make a misstep.
The reason for this is that you do not want to be viewed as someone who is a ‘slacker’ but at the same time you also do not want to be thought of as someone who is a workaholic either. Remember that normal working hours can be different in different companies. What is a standard work week in one company might consist of 40 hours while in another it could be comprised of 60 hours per week or even more. Unless you are very familiar with that company and what they consider to be a standard work week, you could easily find yourself in dangerous territory if you answer this question too specifically.
Some people automatically associate working a lot of hours with being ambitious and productive, but you should also realize that there can be a negative connotation to working a lot of hours as well. The interviewer could see this as an indication that you are not productive enough in order to get the work done within what is considered to be a reasonable amount of time and as a result may be hesitant about hiring you for that particular job.
This is precisely why you should make sure you stick with a safe answer when responding to this type of question unless you are very certain about the expectations of the company and the culture of that company. Instead, you should focus your answer on indicating that you are willing and able to work as much as is needed in order to get the job accomplished. This type of answer will ensure that you do not drift into dangerous ground. This answer will also ensure that you demonstrate to the interviewer your dedication and commitment to getting the job done.