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You are asked to design a shaving mirror...

You are asked to design a shaving mirror assuming that a person keeps it `10cm` from his face and views the magnified image of the face at the closest comfortable distance of `25cm`. The radius of curvature of the mirror would then be:

A

60 cm

B

30 cm

C

24 cm

D

`-24 cm`

Text Solution

Verified by Experts

The correct Answer is:
A

`(1)/(f) = (1)/(25) + (1)/(-10) = (10 - 25)/(10+ 25)`
`implies f = (-50)/(3)`
`R = 2f = -(100)/(3) = -33.33 cm`
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Knowledge Check

  • A small candle, 2.5 cm in size is placed at 27 cm in front of a concave mirror of radius of curvature 36 cm. At what distance from the mirror should a screen be placed in order to obtain a sharp image ? Describe the nature and size of the image. If the candle is moved closer to the mirror, how would the screen have to be moved ?

    A
    `-54` cm
    B
    `+54` cm
    C
    `-11` cm
    D
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  • Double-convex lenses are to be manufactured from a glass of refractive index 1.55, with both faces of the same radius of curvature. What is the radius of curvature required if the focal length is to be 20cm ?

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    102 cm
    B
    55 cm
    C
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    D
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