A) 18 cm, 2 cm
B) 11 cm, 9 cm
C) 10 cm, 10 cm
D) 15 cm, 5 cm
Correct Answer: A
Solution :
[a] \[\frac{{{f}_{0}}}{{{f}_{e}}}=9,\] \[\therefore {{f}_{0}}=9{{f}_{e}}\] Also \[{{f}_{0}}+{{f}_{e}}=20\] (\[\therefore \]final image is at infinity) \[9{{f}_{e}}+{{f}_{e}}=20,\,{{f}_{e}}=2\,\,cm,\] \[\therefore {{f}_{0}}=18\,cm\]You need to login to perform this action.
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