A can of beer (12 oz), a glass of wine (5-6 oz), and a 1.5 oz shot of whiskey all generally contain the same amount of alcohol. It should be noted these are 3 different serving sizes, indicating there is more alcohol in whiskey, less in wine, and the least in beer.
First there needs to be a little clarification:
Wine usually isn't seved in "shots". A general serving for comparison purposes is about five ounces.
Whiskey comes in varying concentrations or strengths. They range from around 40 % alcohol to 80%. Again, for comparison purposes, 40% (or "80 proof") whiskey, or spirits, is a good concentration.
With this in hand, a 5 ounce glass of wine, a 12 ounce can of general American beer, and a 1 1/2 ounce shot of 49% whiskey contain approximately the same amount of alcohol.