Rape in the first degree

(1) A person is guilty of rape in the first degree when: (a) He engages in sexual intercourse with another person by forcible compulsion; or (b) He engages in sexual intercourse with another person who is incapable of consent because he: 1. Is physically helpless; or 2. Is less than twelve (12) years old. (2) Rape in the first degree is a Class B felony unless the victim is under twelve (12) years old or receives a serious physical injury in which case it is a Class A felony.