1. claudius's comment in scene 1 that he is happy to hear of hamlet's interest in the troupe of actors is an example of dramatic irony because

Dramatic irony occurs in a piece of literature when the audience knows something that some characters in the narrative do not. The spectator of a play, or reader of a novel or poem, thus has information that at least some of the characters are unaware of, which affects the way the audience member reacts to the plot. For example, the reader might be aware that a certain trap has been set and feels suspense when an unknowing character is about to walk right into this trap. The tension of the piece therefore depends on the contrast between what the audience and characters know.