10th Class Science Solved Paper - Science-2016 Outside Delhi Set-I

  • question_answer
    (a) Define optical centre of a spherical lens.
    (b) A divergent lens has a focal length of 20 cm. At what distance should an object of height 4 cm from the optical centre of the lens be placed so that its image is formed 10 cm away from the lens. Find the size of the image also.
    (c) Draw a ray diagram to show the formation of image in above situation.


    (a) Optical centre is a point on a lens through which ray of light passes undeviated, without suffering any refraction.
    (b) Given: \[f=\text{ }20\text{ }cm,\text{ }{{h}_{0}}=4\,cm,\text{ }v=\,\,10\,cm\]
                We know that,
                Now,     \[m=\frac{hi}{ho}=\frac{v}{u}\]
    \[\Rightarrow \]               \[{{h}_{i}}=2\mathrm{cm}\]                            


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