A) 15 cm
B) 6 cm
C) 30 cm
D) 24 cm
Correct Answer: C
Solution :
Here: \[_{a}{{n}_{g}}=\frac{3}{2}{{,}_{a}}{{n}_{\omega }}=\frac{5}{4},{{f}_{1}}=12\,cm\] \[\therefore \] \[_{\omega }{{n}_{g}}=\frac{_{a}{{n}_{g}}}{_{a}{{n}_{\omega }}}=\frac{3/2}{5/4}=\frac{6}{4}\] \[\frac{{{f}_{2}}}{{{f}_{1}}}=\frac{{{(}_{a}}{{n}_{g}}-1)}{{{(}_{a}}{{n}_{\omega }}-1)}\] Or \[\frac{{{f}_{2}}}{12}=\frac{(3/2-1)}{(6/5-1)}\] Or \[{{f}_{2}}=\left( \frac{1/2}{1/5} \right)\times 12\] Hence, \[{{f}_{2}}=30\text{ }cm\]You need to login to perform this action.
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