On an electric stove, does the smaller burner produce fewer BTUs than the larger burner?
Electric stove elements have a different KW rating depending on construction and size

A typical spiral element of 200 mm (8") diameter will be 2 KW, a 150 mm (6") diameter element will be 1.3 KW

Different stove makes and models have different ratings. But not many go above 2 KW, except in USA where they go up to 3 KW

Stove makers usually publish exact specifications on their web sites

1 W is approximately 3.4 BTU