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The distance between an object and the s...

The distance between an object and the screen is 100cm. A lens produces an image on the screen when the lens is placed at either of the positions 40cm apart. The power of the lens is nearly

A

3 D

B

5 D

C

7 D

D

9 D

Text Solution

Verified by Experts

The correct Answer is:
B
`D=100cm,x=40cm`
`f=(D^2-x^2)/(4D)=((100)^2-(40)^2)/(4xx100)`
`=((100+40)(100-40))/(400)=(140xx60)/(400)=21cm`
`P=(100)/(f(cm))=(100)/(21)=5D`
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CP SINGH-REFRACTION AT SPHERICAL SURFACES-EXERCISES
  1. The distance between the object and the screen is d (greater than 4 ti...

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  2. In displacement method, the lengths of images in the two positions of ...

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  3. The distance between an object and the screen is 100cm. A lens produce...

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  4. A screen is placed a distance 40 cm away from an illuminated object. A...

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  5. In an experiment with a lens the object distance u versus image distan...

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  6. The graph between the object distance along the X-axis and image dista...

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  7. The graps shows the variation of magnification m produced by as conve...

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  8. In an optics experiment, with the position of the object fixed, a stud...

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  9. A student measures the focal length of a convex lens by putting an obj...

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  10. The graph between the lateral magnification (m) produced by a lens and...

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  11. For a convex lens, if real image is formed the graph between (u+v) and...

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  12. Diameter of a plano-convex lens is 6cm and thickness at the centre is ...

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  13. An object is placed at a distance x1 from the principal focus of a len...

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  14. A point object O is placed on the principal axis of a convex lens of f...

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  15. An illuminated object is placed on the principal axis of a converging ...

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  16. A split lens has its two parts separated by a and its focal length is ...

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  17. When a biconvex lens of glass having refractive index 1.47 is dipped i...

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  18. A convex lens if in contact with concave lens. The magnitude of the ra...

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  19. Two plano-concave lenses (1 and 2) of glass of refractive index 1.5 ha...

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  20. Two similar planoconvex lenses are combined together in three differen...

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