Arguments are either valid or invalid. All valid arguments are good and invalid arguments are bad. A bad argument is also fallacious. Therefore, in the strict sense of the term, whatever causes an invalid argument also causes a fallacy.
“Argument ad Populum” is a fallacy which is committed when a speech appeals to emotion and stirs up love or hatred. Generally, political speeches fall under this category. A classic example of this fallacy finds place in Shakespeare’s Julius Caser, when Mark Antony instigates the crowd to take revenge on Caesar’s killing. It should be noted that in such case the appeal is striking and hence it is noticeable easily.