Section C: Give a short answer to the question given below.
31. The power of a lens is \(+4\ D\). Find the focal length of this lens. An object is placed at a distance of \(50\ cm\) from the optical centre of this lens. State the nature and magnification of the image formed by the lens and also draw a ray diagram to justify your answer.
The focal length of the lens is .
The image is formed the lens.
The image distance is .
The magnification of the lens is .
The formed image is .