Beginning cooks often ask for the "temperature" they have to use to cook their food. What matters in reality is not the temperature, but the speed of heat transfer. And that is dependent on a lot of variables: type of food, amount of food, how much is it piled, pan size, pan material, and of course how much energy your stove is pumping out, which is correlated (but not 1:1) to how much energy your stove is consuming from the power socket or gas pipe. Aside from a narrow choice of pans, the only thing you can control during cooking is the amount of energy your stove consumes.
So, you could look up the BTU, but it won't tell you much. You can try turning the knob to the middle, but that rarely produces a medium heat, because all the other variables would have to be right. In the end, there is no "medium heat" stove setting. What people mean when they say "medium heat" is the setting in which the food happens to cook in a certain way, between searing and stewing in its own leaking juices which don't manage to evaporate in time. If you are talking liquid instead of dry pieces, it is the heat which can sustain a strong simmer or slow boil. It takes a bit of experience to recognize when it is happening.
The "food gets done in 10 instead of 5 minutes" is irrelevant. First, the time can vary with variables you have no control with. Second, recipes give bad timings for a plethora of reasons. Some have a wrong feeling of how long it takes and jot it down, others may have timed it for a smaller portion, third can have literally been told by the marketing department to round down aggressively, fourth may do it because a myth has been established and they believe it more than their own experience (see the infamous Slate complaint on caramelized onions). Whatever the reason, the times given in a recipe don't matter much. You recognize that your food is cooking at the correct speed if its state is changing the way it should (which requires some experience) and that it is ready by noticing that it has reached its desired state (which requires either experience or a thermometer).
So, the conclusion: your cooktop has the proper power for home cooking - basically all cooktops sold to home cooks do. You simply need to turn the knob until the food is cooking the way it should, regardless of any considerations about how much it should be turned or how long your food should be taking.