[" Wettion "21." (a) Determine the effective focal length' of the "],[" combination of the two lenses in question "10" ,if they are placed "],[80cm" apart with their principal axes coincident.Does the answer "],[" depend on which side of the combination a beam of parallel light is "],[" incident? Is the notion of effective focal length of this system useful "],[" at all? "]

Determine the .effective focal length. of the combination of the two lenses in Exercise 9.10, if they are placed 8.0 cm apart with their principal axes coincident. Does the answer depend on which side of the combination a beam of parallel light is incident ? Is the notion of effective focal length of this system useful at all .

a. Determine the 'effective focl length ' of the combination of the two lenses in Exercise 9.10, if they are placed 8.0 cm apart with their principal axes coincident . Does the answer depend on which side of the combination a beam of parallel light is incident? in the notion of effective focal length of this system useful at all ?

a) Determine the effective focal length of the combination of the two lenses in Exercise, if they are placed 8.0cm apart with their principal axes coincident. Does the answer depend on which side of the combination a beam of paralel light is incident? Is the notions of effective focal length of this system useful at all? b) An object 1.5 cm in size is placed on the side of the convex lens in the arrangement a) above. The distance between the object and the convex lens is 40cm. Determine the magnification produced by the two-lens system, and the size of the image.