Well, most active and passive basses when you don't use EQ are very similar. After all, the front end of your head is basically an active preamp! An active bass merely moves part of that EQ circuit into the bass where it more convenient to adjust while you are playing.
In the Common Application, it says that the Personal Essay should be at least 250 words, and attached on a separate sheet (presumably, if you're submitting it online, you attach a one-page file).
If you are wondering how long each part of an essay (the introduction, the body and the conclusion) should be, here are some ideas of how to balance the length. The overall length of an essay will often depends on how big the topic is.