Answer: Excitement
The tone of a text refers to the emotions that the reader feels when reading the piece. Tone can be created in several ways. The author can shape the tone of the text through the actions of the characters. He can also do it by chosing certain words over others or chosing words that have particular connotations. In this case, Johan "burst" through the kitchen, which means that he was experiencing an intense emotion. His wife smiled, and wanted his mother to open the letter. All these actions convey a feeling of excitement.
