InterviewSolution
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InterviewSolution
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Figure, shows variation of magnification m (produced by a thin convex lens) and distance v of image from pole of the lens. When of the following statements are correct? A. Focal length of the lens is equal to intercept on v-axisB. Focal length of the lens is equal to inverse of slope of the lineC. Magnitude of intercept on m-axis is equal to unityD. None of the above |
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Answer» Correct Answer - a.,b.,c. `(1)/(v)-(1)/(u)=(1)/(f)` `1-(v)/(u)=(v)/(f)` (i) Since m is positive in the given figure, therefore m represents magnitude of the magnification. In fact, if a real image is formed by a convex lens, then the image and object will be on opposite sides of the lens. It means, if v is positive, then u will be negative . Therefore, `m=|(v)/(u)|=-(v)/(u)` (ii) Hence, Eq. (i) becomes `m=v/(f)-1` It means, the graph between m and v will be a straight line having intercept `-1` on m-axis and slope of the ling `tantheta` is equal to `(1//f)`. Hence, option (b) and (c) are correct. Putting `m=0` in Eq. (ii), `v=f` . Hence (a) is also correct. Obviously, (d) is wrong. |
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