JCECE Engineering JCECE Engineering Solved Paper-2007

  • question_answer
    A telescope has focal length of objective and eyepiece as \[200\,\,cm\] and \[5\,\,cm\] respectively. What is magnification of telescope?

    A) \[40\]                                   

    B) \[80\]

    C)  \[50\]                                  

    D) \[0.01\]

    Correct Answer: A

    Solution :

    In relaxed eye state of telescope or when final image is formed at infinity, the magnification of telescope is given by                 \[|M|\,\,=\frac{{{f}_{o}}}{{{f}_{e}}}\] where \[{{f}_{0}}=\] focal length of objective\[=200\,\,cm\] \[{{f}_{e}}=\]focal length of eyepiece\[=5\,\,cm\] Hence,  \[|M|\,\,=\frac{200}{5}=40\] Note: The aperture of the objective lens is kept large so that more and more rays coming from the heavenly body may enter the telescope and a bright image is formed by the objective lens. The aperture of the eye lens is kept comparatively small so that all the rays may enter the eye.


You need to login to perform this action.
You will be redirected in 3 sec spinner