![a) Determine the 'effective focal length' of the combination of the two lenses in Exercise 9.10, if they are placed 8.0 cm apart with their principal axes coincident. Does the answer depend a) Determine the 'effective focal length' of the combination of the two lenses in Exercise 9.10, if they are placed 8.0 cm apart with their principal axes coincident. Does the answer depend](https://d10lpgp6xz60nq.cloudfront.net/physics_images/U_LIK_SP_PHY_XII_C09_E01_021_S01.png)
a) Determine the 'effective focal length' of the combination of the two lenses in Exercise 9.10, if they are placed 8.0 cm apart with their principal axes coincident. Does the answer depend
![Physics 55.4 Optics- Multiple Lenses (3 of 12) The Double Lens: The Equivalent Focal Length - YouTube Physics 55.4 Optics- Multiple Lenses (3 of 12) The Double Lens: The Equivalent Focal Length - YouTube](https://i.ytimg.com/vi/GxemspUuOSU/hqdefault.jpg)
Physics 55.4 Optics- Multiple Lenses (3 of 12) The Double Lens: The Equivalent Focal Length - YouTube
![homework and exercises - Inserting thick lenses into a thin lens system and deducing values - Physics Stack Exchange homework and exercises - Inserting thick lenses into a thin lens system and deducing values - Physics Stack Exchange](https://i.stack.imgur.com/BWJcI.png)
homework and exercises - Inserting thick lenses into a thin lens system and deducing values - Physics Stack Exchange
When two thin lenses are kept in contact, prove that their combined or effective focal length F is given by 1/F = 1/f1 + 1/f2 where the terms have their usual meaning.
![Physics 55.4 Optics- Multiple Lenses (3 of 12) The Double Lens: The Equivalent Focal Length - YouTube Physics 55.4 Optics- Multiple Lenses (3 of 12) The Double Lens: The Equivalent Focal Length - YouTube](https://i.ytimg.com/vi/GxemspUuOSU/mqdefault.jpg)
Physics 55.4 Optics- Multiple Lenses (3 of 12) The Double Lens: The Equivalent Focal Length - YouTube
![When two thin lenses are kept in contact prove that their combined or effective focal length F is given by 1F1F11F2 where the terms have their usual meaning When two thin lenses are kept in contact prove that their combined or effective focal length F is given by 1F1F11F2 where the terms have their usual meaning](https://content-grail-production.s3.amazonaws.com/quetsion-media/24066af9-5039-4636-b492-415c8f1e7ec2-image.png)