# NEET Physics Ray Optics and Optical Instruments Questions Solved

NEET - 2015

In an astronomical telescope in normal adjustment a straight black line of length L is drawn on inside part of objective lens. The eye-piece forms a real image of this line. The length of this image is l. The magnification of the telescope is

(a)L/l+1

(b)L/l-1

(c)L+1/L-1

(d)L/l

We know,magnification of telescope,we have

M=$\frac{{f}_{0}}{fe}$

Here, =>fe/fe+u=-l/L

=> fo/fe-(fo+fo)=-l/L

=>fe/fo=l/L

i.e. M=L/l

Difficulty Level:

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