An object is placed at a distance of 30cm from a converging lens of focal length 15cm. A normal eye (near point 25cm, far point infinity) is placed close to the lens on the other side.
- Can the eye see the object clearly?
- What should be the minimum separation between the lens and the eye so that the eye can clearly see the object?
- Can a diverging lens, placed in contact with the converging lens, help in seeing the object clearly when the eye is close to the lens?
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Object distance, u = -30cm Focal length, f = 15cm Image distance, v = ? The lens formula is given by$\frac{1}{\text{v}}-\frac{1}{\text{u}}=\frac{1}{\text{f}}$
$\Rightarrow\frac{1}{\text{v}}-\frac{1}{-30}=\frac{1}{15}$
$\Rightarrow\frac{1}{\text{v}}=\frac{1}{30}$
$\Rightarrow \text{v}=+30\text{cm}$
(on the opposite side of the object)
$\Rightarrow\frac{1}{\text{v}}-\frac{1}{-30}=\frac{1}{15}$
$\Rightarrow\frac{1}{\text{v}}=\frac{1}{30}$
$\Rightarrow \text{v}=+30\text{cm}$
(on the opposite side of the object)
- No, the eye placed close to the lens cannot see the object clearly.
- The eye should be 30cm away from the lens to see the object clearly.
- The diverging lens will always form an image at a large distance from the eye this image cannot be seen through the human eye.
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