This inconsistency in your belief and in your action is what is referred to as cognitive dissonance.
Cognitive dissonance can be defined as the conflicting attitude that people may have. This can be described as a situation where a person is having conflicting beliefs and attitudes.
In the question, we can easily see this. The person already knows that to have good grades, they owe it to themselves to study hard. Yet they still keep on watching the television.
