Saved Bookmarks
| 1. |
Two convex lenses of same focal length but of aperture A_(1) and A_(2)(A_(2)ltA_(1)), are used as the objective lenses in two astronomical telescopes having indentical eyepieces. What is the ratio of their resolving power ? Which telescope will you prefer and why ? Give reason. |
|
Answer» Solution :We know that resolving power of a TELESCOPE is given by the relation `R.P.=(A)/(1.22lamda)` where A=aperture of objective LENS of telescope and `lamda=`wavelength of light used. as apertures of two telescope objectives are `A_(1) and A_(2) and A_(1) gt A_(2)`, hence `((R.P.)_(1))/((R.P.)_(2))=(A_(1))/(A_(2))implies(R.P.)_(1)gt(R.P.)_(2)`. As focal LENGTHS of lenses of two telescopes are equal, hence their magnifying powers are equal, but resolving power of telescope NUMBER 1 is more, hence we shall prefer this telescope having aperture of objective `A_(1)`. |
|