Q.19 There is a fixed point object at point A. There is a screen at position B. A converging lens of focal length f cm is kept at position C as shown and a sharp image of the object is obtained on the screen. Now the lens is kept at position G. Again, a sharp image of the object is obtained on the screen. Distance AB = 25 cm and distance between the two positions of the lens is 5 cm. Calculate f in cm. C G