.An object placed 10 cm in front of a lens has an image 20 cm behind the lens. What is the power of the lens
.An object placed 10 cm in front of a lens has an image 20 cm behind the lens. What is the power of the lens
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Given :
Object distance= u= - 10cm [ assumed as convex lens ]
Image distance=v=20cm
focal length = f= 1/v-1/u
= 1/20+1/10
1/f= 3/20
Power = P= 100/f ( in cm)
P= 100x3/20
=300/20
=+15 D
∴ power of lens is +15D.
Answer:
The power of the lens is 15 D.
Explanation:
Given that,
Distance of the object u = -10 cm
Distance of the image v = 20 cm
Using lens's formula
Put the value into the formula
The power of the lens is the reciprocal of its the focal length.
The power of the lens is defined as:
Hence, The power of the lens is 15 D.