Detonator cap is situated at -

Ans. is 'c' i.e., Base of the rim * Centre of base has percussion cap (detonator cap) which has sensitive composition, i.e., primer, consisting of potassium chlorate, antimony sulphide, mercury fulminate, barium nitrite, lead peroxide or tetrazene.* Cartridge case of shot gun is filled in following order (Starting from base)# Percussion (detonator) cap or primer battery cup.# Gun powder# Thick felt wad with carboard discs lying in front and behind.# Lead shot# Retaining cardboard (overshot/top-wad)