66.From ray diagram show the (1) image formation by concave lens for the object at focus. (2) image formation by concave lens for the virtual object at focus
Why is it that a virtual image formed by lenses can be seen by the naked eye but cannot be projected on a screen? - Quora
![Optical ray diagram of dual-lens operation. A magnified virtual image... | Download Scientific Diagram Optical ray diagram of dual-lens operation. A magnified virtual image... | Download Scientific Diagram](https://www.researchgate.net/publication/261174912/figure/fig2/AS:296835727020032@1447782560046/Optical-ray-diagram-of-dual-lens-operation-A-magnified-virtual-image-of-OL-first.png)
Optical ray diagram of dual-lens operation. A magnified virtual image... | Download Scientific Diagram
![A convex lens forms a virtual image of an object. The position of the object is between optical centre and focus. A convex lens forms a virtual image of an object. The position of the object is between optical centre and focus.](https://haygot.s3.amazonaws.com/questions/1134358_1015079_ans_0ea816b49a3a4e1d86441a3e4edf6f3f.png)