A dentist mirror has a radius of carvature of 3cm. how far must it be placed to give a virtual image that is magnified three time.
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A dentist mirror has a radius of carvature of 3cm. how far must it be placed to give a virtual image that is magnified three time.
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Explanation:
R= 3cm,
f =- 3/2 = -1.5cm ( Negative sign for cancave mirror)
m = 5
We know that m= - v/u
Therefore (-5u) =( v)
Using (1/v) + (1/u) = (1/f )
(1/-5u) + ( 1/u) = (1/-1.5)
Therefore, (5u /4) = -1.5
Thus, u = -1.2 cm
The object should be placed at a distance of 1.2cm from the mirror to get 5 times magnified image.
Explanation:
the mirror should be placed 1.25 cm away from the dental cavity.