converging beam of light forms a sharp image on a screen.A lens is placed 10 cm from the screen in the path of thebeam. It was found that the screen has to be moved 8 cmfurther away to obtain the sharp image. Focal length of the

Q. A converging beam of the light forms a sharp image on a screen. A lens is placed in the path of the beam, the lens being $10cm$ from the screen. It is found that the screen has to be moved $8cm$ further away from the lens to obtain a sharp image. Find the focal length and nature of lens.

Q. A converging becam of light forms a sharp image on a screen. A lens is placed in the path of the beam, at $10\text{cm}$ from the screen, it is found that the screen has to be moved $8\text{cm}$ further away from the lens to obtam a sharp image. The focal length and the nature of lens is.

Q. An object is placed $30cm$ away from a convex lens of focal length $10cm$ and a sharp image is formed on a screen. Now a concave lens is placed in contact with the convex lens. The screen now has to be moved by $45cm$ to get a sharp image again. The magnitude of focal length of the concave lens is (in $cm$):

Q. A thin converging lens of focal length $f=25cm$ forms the image of an object on a screen placed at a distance of $75cm$ from the lens. The screen is moved closer to the lens by a distance of $25cm$. The distance through which the object has to be shifted so that its image on the screen is sharp again is:

Q. An object and a screen are mounted on an optical bench and a converging lens is placed between then so that a sharp image is obtained on the screen. The linear magnification of the image is $25$. The lens is now moved $30cm$ towards the screen and a sharp image is again formed on the screen. Find the focal length of the lens.