For a diagram see:
http://www.funscienceforgirls.com/2010/11/spy-week-periscope.html
It uses two plane mirrors
WHAT TYPE OF MIRRORS ARE USED IN A PERISCOPE(CONCAVE, CONVEX?) ALSO,DRAW A RAY DIAGRAM OF A PERISCOPE
4 answers
See also
http://www.google.com/images?hl=en&q=how+a+periscope+works+diagram&bav=on.2,or.r_gc.r_pw.&wrapid=tlif130054337423810&um=1&ie=UTF-8&source=univ&sa=X&ei=mLeETZqnKY76swOr7byDAg&ved=0CCQQsAQ&biw=1393&bih=646
http://www.google.com/images?hl=en&q=how+a+periscope+works+diagram&bav=on.2,or.r_gc.r_pw.&wrapid=tlif130054337423810&um=1&ie=UTF-8&source=univ&sa=X&ei=mLeETZqnKY76swOr7byDAg&ved=0CCQQsAQ&biw=1393&bih=646
IT DOESNT USE MIRRORS. IT USE 2*45 DEGREE GLASS PRISMS.THERFORE IT UNDERGOES TOTAL INTERNAL REFLECTION AND REFLECTS TWICE MAKING THE PERSON ABLE TO SEE
Concave