There were several reasons why the French were defeated by the British in North America
during the course of the Seven Years' War (1756-1763) in Europe.

Reasons for the British Conquest

New France had a vast territory but a small  population to defend it.

Britain's navy was stronger and bigger and they could prevent supply ships from reaching New France. New France had 5000 soldiers compared to 23,000 soldiers in the 13 Colonies.  The population of the 13 Colonies was about 1.5 million in 1760; that of New France was about 70,000.  The 13 Colonies has a stronger, more diversified economy than New France. New France was too reliant on France because of mercantilism. France was preoccupied with war in Europe and could not afford to send much help.  On September 13, 1759 the English and French forces met on the Plains of Abraham. After a brief but bitter struggle, in which both Montcalm and Wolfe were killed, Quebec fell to the British. With the defeat of the French, at Sainte-Foy and Montreal  in 1760, New France was conquered and came under British rule.

Interpretations of the Conquest
Nationalist historians, such as Guy Frégault, view the Conquest as a turning point in
Quebec's history. According to Frégault, the Conquest brought about New France's ruin
since it lost its territory and its political and economic leadership. Consequently, it came to
be increasingly dominated by the Catholic Church. Other historians, such as Fernand Ouellet,
state that the Conquest had little impact on the evolution of French Canadian society.

Try the following questions on the causes of the Conquest.