What is an author's tone when they give information about a topic?

It depends what they are talking about. 

If they are talking about the bombing of 9/11 then the tone would be serious, sad, mad at the other country for doing what they did. 
But, if they are talking about a major- fun holiday- like Halloween then the tone would happy, excited, energetic! It just depends what the topic the author is talking about!!
Hoped this helped you! :))  

The author's tone is descriptive because is giving information about the topic.
HOPE THIS HELPS!!

To kill a mockingbird, which was published in 1960, go set a watchman is actually that novel's first draft. the novel was finished in 1957 and purchased by the j.b.