You are given the following three lenses. Which two lenses will you use as eyepiece and as an objective to construct a compound microscope ? .
`{:("Lenses","Power(D)","Aperture(cm)"),(L_1,3,8),(L_2,6,1),(L_3,10,1):}`

You are given the following three lenses. Which two lenses will you use as eyepiece and as an objective to construct an astronomical telescope? Give reason . {:("Lenses","Power(D)","Aperture(cm)"),(L_1,3,8),(L_2,6,1),(L_3,10,1):}

Two lenses of focal lengths 6cm and 50 cm are used in construction of a telescope. Which lens will be used as an objective and why?

Two convex lenses of focal lengths f_1 and f_2 respectively are placed in contact each other. Then what will be power of their equivalent lens?

The focal lengths of the eyepiece and the objective of a microscope are 0.3 m and 0.4 and the distance between them is 0.2m . The position of the eyepiece and the objective are so interchanged that the angular magnification of the instrument remains unchanged. What is the new distance between the two lenses ?

The lengths of a compound telescope is 21.5 cm . The focal lengths of its objective and eyepiece are 1.6 cm and 2.1 cm respectively . If the final image is formed at a distance of 22.45 cm from the eyepiece , then calculate the distance of the object from the objective.