A) 30 cm
B) 60 cm
C) 120 cm
D) 240 cm
Correct Answer: C
Solution :
By using\[\frac{{{f}_{l}}}{{{f}_{a}}}=\frac{{{(}_{a}}{{\mu }_{g}}-1)}{{{(}_{l}}{{\mu }_{g}}-1)}\Rightarrow {{f}_{w}}=4{{f}_{a}}=4\times 30\]=120 cm.You need to login to perform this action.
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