In an astronomical telescope in normal adjustment, a straight black line of the length L is drawn on the objective lens. The eye-piece forms a real im - Physics MCQ Physics | ExamTest.live

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

A $\frac{L}{I}$
B $\frac{L}{I} + 1$
C $\frac{L}{I} - 1$
D $\frac{L + I}{L - I}$

Solution & Step-by-step Explanation

1. In normal adjustment, the objective and eyepiece are separated by f_{o} + f_{e} .2. The line of length L is at distance u = f_{o} + f_{e} from the eyepiece.3. Magnification by eyepiece m = \frac{v}{u} = \frac{f}{f + u} .4. m = \frac{f _{e}}{f _{e} - ( f _{o} + f _{e} )} = \frac{f _{e}}{- f _{o}} .5. Also m = \frac{I}{L} \Rightarrow \frac{I}{L} = \frac{f _{e}}{f _{o}} (ignoring sign for magnitude).6. Magnification of telescope M = \frac{f _{o}}{f _{e}} = \frac{L}{I} .

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

\frac{L}{I}

\frac{L}{I} + 1

\frac{L}{I} - 1

\frac{L + I}{L - I}

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

Solution & Step-by-step Explanation

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

Solution & Step-by-step Explanation

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Discussion

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