I would agree with other posters that guilt and shame are probably the most common emotions we think of when a child has been abused. I also think that as the child grows and reaches adolescence we see the anger come out at that time.
I think in America, we try to teach children that they control their own destiny. We set out choices and consequences - both good ones and bad, and children quickly learn that, yes, this is a place where you can certainly make yourself who you want to be if you take control of your own future. Abused children, to me, seem to not get this concept. It's like they are trapped. They feel controlled, instead of in control. Unfortunately, some Americans take more that their due portion of control, but I think that the issue of learning how to control yourself and understand the impact on your own future is something victims of child abuse struggle with severely.
Guilt and shame are givens. Fear, and anger are also emotions these children will experience. If not dealt with, the children who suffered the abuse will either become very withdrawn and afraid of intimacy (issues with ever finding real love and fostering trusting relationships with the opposite gender) or will be incredibly promiscuous as a result of feeling worthless and used by an adult who should have been a trusted protector. Some who have been abused as children also take their anger out on other children... therefore, becoming abusers themselves, and continuing the whole rotten cycle.
Guilt and shame, of course, are the longest-lasting emotions which are experienced by abused children. We know that to be true as we hear story after story by adults--many of them older adults--who are only able to share their experiences years after the abuse occurs. (Think of all the adults who were abused by Catholic priests or Boy Scout leaders who have only spoken up years after the fact.) Shorter-term effects are more complicated, as the abused are generally still within the grasp, so to speak, of the abuser. Long term, though, guilt and shame are the overwhelming emotions experienced by those who have been abused.
Child abuse is a spectrum of abuse. A progression, often as well. Abusers usually are, by nature, master manipulators, and systematically destroy the victim's self-esteem and sense of self worth, or in the most extreme cases, raise children who have none to begin with.
This is one of the things, I think, that leads to guilty feelings on the part of the victim, as they were groomed (a law enforcement term for when an abuser develops a situation/person so abuse is possible/easier) to believe they were responsible.
As an educator, I have seen several situations where I suspected child abuse and occasionally confirmed it via discussions with the child. the thing that struck me the most is the sense of responsibility that abused children feel for what has been perpetrated on them by the adult.
So many times the child feels that if she were better behaved, prettier, more of what the parent wants, then the abuse would not be occurring. These feelings of inadequacy and responsibility alternate with anger that the abuse is occurring and the desire to escape it. Add into that mix a strong love for the abusive parent, in most cases, and it is a toxic stew of emotions that causes terrible damage to the child's spirit.
I think that many children somehow try to blame themselves. They will wonder what they did wrong or what they can do better. This is really sad but it's true. Sometimes children will often act out as well. They are filled with emotions such as anger, sadness, loneliness, guilt, and fear and the only way they know how to release their emotions is through acting out.
I second "guilt." Many victims of abuse cannot let go of the thought that it is somehow their fault.
Another common emotion/reaction (especially much later) is to continue to feel victimized in other aspects of life - especially relationships. Many victims of physical and emotional abuse thrive off the familiarity of the feelings abuse causes - and so continue to seek it. This is why so many battered women have been in more than one abusive relationship. They are drawn to abuse, some believe, because they think they deserve it.