A wild rose 1.2 cm in diameter is 90.0 cm from a camera's zoom lens. The focal length of the lens has a magnitude of 150.0 mm.What is the distance between the lens and the camera film where the image of the rose is formed? 

The focal length of a digital camera is 7.50 cm.It focuses on an object 1.85m tall which is 4.25 m away from the lens.How far must the lens be from the sensor array?

An object is placed $15\ cm$ from a diverging mirror of radius of curvature $20\ cm$. What is the image magnification produced?

Two plano-convex lenses of focal lengths $f$ and $2 f$ are coaxially separated so that the spherical aberration is minimized. The effective focal length of the combination is :

Fill in the blanks:
The equation of mirror formula is ___