Should I write soo much in theory exams like minimum 20 pages to score good marks

Iam in S4 now and for yesterday's renewable energy and sources exam most people wrote minimum 17 pages and some have wrote about 22 pages but I havent written that much so will I get less marks.In earlier semester in subjects like entrepreneurship and ethics I haven't written that much and still scored very good marks but I highly doubt that to happen in this semester.