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A convex lens of diameter 8.0 cm is used...

A convex lens of diameter 8.0 cm is used to focus a parallel beam of light of wavelength 620 nm. If the light be focused at a distance of 20 cm from the lens, what would be the radius of the central bright spot formed ?

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The correct Answer is:
A, C
`lamda =620nm =620xx10^-9m,
D=20cm=20xx10^-2m,
d=8cm=8xx10^-2m`
`:.R=1.22xx(620xx10^-9xx20xx10^-2)/(8xx10^-2)`
`=1891xx10^-9`
`=1.9xx10^-6m`
So, diameter `=2R=3.8xx10^-6m`
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  5. Consider the arrangement shown in figure. The distance D is large comp...

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  7. figure shows three equidistant slits illuminated by a monochromatic pa...

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  8. In a Young's double slit experiment, the separation between the slits ...

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  9. In a Young's double slit interference experiment the fringe pattern is...

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  10. In a Young's double slit experiment lamda= 500nm, d=1.0 mm andD=1.0m. ...

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  12. Consider the situation shown in figure. The two slits S1 and S2 placed...

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  13. Consider the arrangement shownin figure. By some mechanism,the separat...

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  15. A parallel beam of light of wavelength 560 nm falls on a thin film of ...

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  16. A parallel beam of white light is incident normally on a water film 1....

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  17. A glass surface is coated by an oil film of uniform thickness 1.00xx10...

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  18. Plane microwaves are incident on a long slit having a width of 5.0 cm....

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  19. Light of wavelength 560 nm goes through a pinhole of diameter 0.20 mm ...

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  20. A convex lens of diameter 8.0 cm is used to focus a parallel beam of l...

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