a dentist mirror has a radius of curvature of 3cm how far must it be placed from a small dental cavity to give a virtual img of the cavity that is magnified 5 times
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Subject: Science (Light-Reflection and Refraction)
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7th Dec 2013, 9:49 PM
A dentist mirror has a radius of curvature of 3 cm . How far must it be placed from a small dental cavity to give a virtual image of cavity that is magnified five times ?
sir , we can ask only one question and your smartlearning shows that you have asked one question . This creates a problem in asking question . kindly give attention to this case .
Smartlearning Expert 9th Dec 2013, 10:35 AM
Accepted Answer:
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.
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Posted By
Student Image
MEGHA
Rate this Question
Currently 0.00/5
Rating: 0.0/5 (0 votes cast)
Subject: Science (Light-Reflection and Refraction)
Status: Closed | Replies: 1
7th Dec 2013, 9:49 PM
A dentist mirror has a radius of curvature of 3 cm . How far must it be placed from a small dental cavity to give a virtual image of cavity that is magnified five times ?
sir , we can ask only one question and your smartlearning shows that you have asked one question . This creates a problem in asking question . kindly give attention to this case .
Smartlearning Expert 9th Dec 2013, 10:35 AM
Accepted Answer:
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.
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