The lecture on Monday April 8 and the exercise class Thursday April 11 will be swapped. This means that Monday will be exercise class (in Kristian Birkeland) and Thurday will be lecture (in V203).
As you won't have too much time to look at the exercise sheet until Monday, this will mainly be more of a repetition class, where we can discuss anything covered in the course until now. To increase the quality of the answer you might get, please feel free to post questions on astro-discourse in advance.
Halvor