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Focal length of the Objective lens is 140 cm. Focal length of the eyepiece is 5cm. If this telescope is used to view a 100 m tall tower 3 km away, what is the height of the image of the tower formed by the objective lens ? |
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Answer» Solution :Angle subtended by the TOWER = `alpha` `alpha = ("height of the power " )/(" DISTANCE between the telescope and tower ") = (100)/(3000) = (1)/(30) ` Let.h. be height of the image. Then `alpha = (h)/(f_(0)) = (h)/(140 ) "" THEREFORE(h)/(140) = (1)/(30) "" h =(140)/(30) = 4.7 ` cm |
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