JEE Main 2007Annual, Paper 1PhysicsEasyOptics190× since 2002Two lenses of power −15-15−15 DDD and +5+5+5 DDD are in contact with each other. The focal length of the combination isAOption A. +10 cm+ 10\,cm+10cmBOption B. −20 cm- 20\,cm−20cmCOption C. −10 cm- 10\,cm−10cmDOption D. +20 cm+ 20\,cm+20cmCheckSkip · show solution
