If you have a low score, the examiner may question whether you know what you need to know, and they may have some ammo for questioning. However, as several others have said, your answers have more to do with the length of a quiz than the score on a knowledge test. Prove you know your stuff and above all, do not make up answers if you don't know. If you're unsure, tell the examiner where you can find the info and look it up right then.