Security lights tend to be wall mounted, very bright and activated by passive infra-red (more commonly referred to as movement sensors or PIR's). The object of security lighting is to deter and detect intruders, security lighting can also be used to create a sense of security and well being if their placement is thought through carefully.   

Around the home security lights often make use of powerful halogen bulbs, these create a very bright light and far beam instantly which can flood light into large areas, this is why they are sometimes called security floodlights. Because security lights tend to be so bright they are often paired up with passive infra-red sensors which effectively detect an intruder approaching and then switch the security lighting on as needed.