PhysicsEasy105×since 2002Q7026Two lenses of power −15-15−15 DDD and +5+5+5 DDD are in contact with each other. The focal length of the combination isA+10 cm+ 10\,cm+10cmB−20 cm- 20\,cm−20cmC−10 cm- 10\,cm−10cmD+20 cm+ 20\,cm+20cmCheck answerSkip