A student used a device (X) to obtain/focus X the image of a well illuminated distant building on a screen (S) as shown below in the diagram. Select the correct statement about the device (X).

Since the object was obtained on the screen, so the image formed was real. So, the lens is convex lens. Moreover, as given in the diagram, the distance between the object and the screen is 8 cm i.e. focal length = 8 cm.