A diverging lens of focal length 30cm produces an image 20cm from the lens. Determine the object distance
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Correct Answer: Option D
Explanation:
Lens formula:
\(\frac{1}{f} = \frac{1}{d_o} + \frac{1}{d_i}\)
where f, d\(_o\) and d\(_i\) are the focal length, object distance and image distance respectively.
⇒ \(\frac{1}{30} = \frac{1}{d_o} + \frac{1}{20}\)
\(\frac{1}{d_o} = \frac{1}{30} - \frac{1}{20}\)
\(\frac{1}{d_o} = \frac{-1}{60}\)
\(d_o = - 60 cm\)
The object distance = 60cm.
Lens formula:
\(\frac{1}{f} = \frac{1}{d_o} + \frac{1}{d_i}\)
where f, d\(_o\) and d\(_i\) are the focal length, object distance and image distance respectively.
⇒ \(\frac{1}{30} = \frac{1}{d_o} + \frac{1}{20}\)
\(\frac{1}{d_o} = \frac{1}{30} - \frac{1}{20}\)
\(\frac{1}{d_o} = \frac{-1}{60}\)
\(d_o = - 60 cm\)
The object distance = 60cm.