A) convex, 9 cm
B) convex, 9 cm
C) convex, 25 cm
D) convex, 25 cm
Correct Answer: A
Solution :
The condition for achromatism is \[\frac{\omega }{\omega '}=-\frac{f}{f'}\] Given: \[\frac{\omega }{\omega '}=\frac{5}{3},\]\[f=-15cm\] So, \[\frac{5}{3}=\frac{-(-15)}{f'}\] or \[f'=+9cm\](convex)You need to login to perform this action.
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