In this chapter, unless a different meaning is plainly required:
(1) "Necessary" means that no reasonably effective alternative to the use of force appeared to exist and that the amount of force used was reasonable to effect the lawful purpose intended.(2) "Deadly force" means the intentional application of force through the use of firearms or any other means reasonably likely to cause death or serious physical injury.1986 c 209 § 1; 1975 1st ex.s. c 260 § 9A.16.010.