Converging Lenses Terminology Optical centre Principal axis Principal focus (side of refracted rays) Secondary principal focus (side of incident rays)
Rules For Converging Lenses 1) Any incident ray parallel to principal axis of a converging lens refracts through lens and through principal focus on opposite side 2) Any incident ray traveling through primary focus will refract through lens and travel parallel to the principal axis 3) An incident ray passing through optical center will continue in same direction
Image Formation by Converging Lens
Images in a Converging Lens OBJECT IMAGE Location Size Attitude Location Beyond 2 F’ Smaller Inverted Between 2 F Real and F At 2 F’ Same size Inverted At 2 F Real Between 2 F’ and F’ Larger Inverted Beyond 2 F Real At F’ No clear image Inside F’ larger Same side as object virtual Upright Type
Diverging Lens
Rules For Diverging Lenses 1) Any incident ray traveling parallel to principal axis will refract through lens and travel in line with the principal focus (i. e. , extension will pass through focal point) 2) Any incident ray traveling towards principal focus will refract through lens and travel parallel to the principal axis.
Rules For Diverging Lenses 3. An incident ray which passes through optical centre will continue in same direction.
Diverging Lens Image Formation Always Virtual, Smaller, and Right-Side Up