![A convex lens A of focal length 20cm and a concave lens G of focal length 5cm are kept along the same axis with the distance between them. If a parallel beam A convex lens A of focal length 20cm and a concave lens G of focal length 5cm are kept along the same axis with the distance between them. If a parallel beam](https://www.vedantu.com/question-sets/5f16a0a5-95d2-4cb5-b754-7a6788995bd93435487036600868184.png)
A convex lens A of focal length 20cm and a concave lens G of focal length 5cm are kept along the same axis with the distance between them. If a parallel beam
![A convex lens of focal length F is placed in contact with a concave lens of focal length F . The equivalent focal length of the combination is: A convex lens of focal length F is placed in contact with a concave lens of focal length F . The equivalent focal length of the combination is:](https://toppr-doubts-media.s3.amazonaws.com/images/1353425/4b922a16-2861-42bf-8b90-2b29fde7abb6.jpg)
A convex lens of focal length F is placed in contact with a concave lens of focal length F . The equivalent focal length of the combination is:
![Lenses in Combination The analysis of multi-lens systems requires only one new rule: The image of the first lens acts as the object for the second lens. - ppt download Lenses in Combination The analysis of multi-lens systems requires only one new rule: The image of the first lens acts as the object for the second lens. - ppt download](https://images.slideplayer.com/23/6905239/slides/slide_3.jpg)