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Find the position of the image formed by the lens combination given in the Fig. |
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Answer» Solution :Image formed by the first LENS `(1)/(v_(1))-(1)/(u_(1))=(1)/(f_(1))` `(1)/(v_(1))-(1)/(-30)=(1)/(10)` The image formed by the first lens serves as the object for the second. This is at a distance of `(15 - 5) cm = 10 cm` to the right of the second lens. Though the image is real, it serves as a VIRTUAL object for the second lens, which means that the rays appear to come from it for the second lens. `(1)/(v_(2))-(1)/(10)=(1)/(-10)` `or v_(2)=oo` The virtual image is formed at an infinite distance to the left of the second lens. This acts as an object for the third lens. `(1)/(v_(3))-(1)/(u_(3))=(1)/(f_(3))` `or (1)/(v_(3))=(1)/(oo)+(1)/(30)` `or v_(3)=30cm` The FINAL image is formed 30 cm to the right of the third lens. |
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