grammar - Passive vs. active form of verb (past) What is the difference?

I was wondering what the difference is if I use passive form or active form of a verb.

For example:

ネズミは猫に食べられた。The mouse was eaten by the cat.

猫は、ネズミを食べた。The cat ate the mouse.

What EXACTLY is the difference between those two? In what situations would I use the passive form to make a sentence.

Or if I were to say:

私は先生にしかられた。I was scolded by the teacher.

先生は私をしかった。The teacher scolded me.

For example, I do not know if this is correct or makes sense:

花子はジョーンが買ったケーキを食べられた。Would this be considered grammatically incorrect in regard to passive form?

Are there situations where I can use に + passive verb? If so, in what cases?

Do Japanese prefer speaking in the passive voice as opposed to active voice? Would it be appropriate to use passive voice instead of directly saying that an action was on on me (say for example: The teacher scolded me).

Thanks so much!!!

Answer

Do Japanese prefer speaking in the passive voice as opposed to active voice?

This is actually an interesting question. I do not think that the Japanese actually consciously prefer passive, but I think there are cases where passive is more idiomatic.

C1. To ease dropping

Japanese is pro-drop, so many things will be dropped if it's obvious from the context. For example, in non-question phrases when no explicit topic is specified, the topic is typically the first person (although this can depend on context, the nature on the sentence, sentence-ending particles etc.):

先生にしかられた I was scolded by the teacher

In English 'The teacher scolded me' is slightly shorter and less complex than 'I was scolded by the teacher', so all other things equal, the first might be prefered. In Japanese, however, the above passive expression is by far the shortest and most idiomatic. '先生が私をしかった' is longer, '先生がしかった' doesn't make it clear who was scolded.

Likewise in question phrases, often the second person is the implicit topic, so to say 'Did the teacher scold you?' or 'Were you scolded by the teacher?'

先生にしかられたの？ Were you scolded by the teacher?

is more idiomatic/precise than '先生があなたをしかったの？' or '先生がしかったの？'. So the passive constructions work better.

C2. To ease free choice of topic

Imagine a story about a mouse. One day our dear mouse is eaten by a cat (which is new to the universe of discourse). In English we can say both 'the mouse was eaten by a cat' or 'a cat ate the mouse'. In this connection, the former might be slightly more natural, but the second works as well. Let's look at this in Japanese:

ある日、猫がねずみを食べた One day, a cat ate a/the mouse.

This is grammatically correct, but it doesn't make it clear that we're talking about our protagonist mouse, it could be any mouse. Therefore, it's really more natural to make the mouse the topic, since topics can only be things already introduced to the universe of discourse. So let's proceed, trying to keep the active voice:

× ある日、ねずみは猫が食べた (One day, it was the cat who ate the mouse)

This doesn't work. When a が is used after a topic-は like this, the が becomes an 'exhaustive が', meaning something like 'it was the cat who ate the mouse'. Others on this site should be better than me at explaining the rules of when がs are neutral vs. exhaustive, it's a topic of its own. In either case, the only option left is really the passive construction:

ある日、ねずみは猫に食べられた One day, the mouse was eaten by a cat.

There are probably other cases as well that I haven't thought of, and there a probably cases where passive is more idiomatic in English, whereas active is more idiomatic in Japanese.