Is it permissible to recite a short Surah in the first Rak'ah and a long Surah in the second Rak'ah of the prayer?

The Sunnah is for the recitation in the first rak'ah to be longer than in the second, as mentioned in the description of the Prophet's prayer (peace and blessings be upon him). He would prolong the recitation in the first rak'ah and shorten it in the second. This is recommended because one's energy is greater in the first rak'ah. However, violating this Sunnah does not invalidate the prayer; it remains valid in all cases.