Why is long shot effective ?

The long shot usually introduces the beginning of every scene. It sets in motion the audience's perception of time, place and logical action of the scene that is about to transpire. For example, the first shot of the sequence of the stagecoach coming into town will normally be shot as a long shot.

Explanation:

cassius, casca, and their allies plant false documents to manipulate brutus to join their cause to remove caesar. after doing so, they visit brutus at night in his home to persuade him of their views. there they plan caesar's death. brutus is troubled but refuses to confide in his devoted wife, portia. on 15 march, caesar's wife, calpurnia, urges him not to go to the senate. she has had visionary dreams and fears the portents of the overnight storms.