A) 20 cm
B) 30 cm
C) 40 cm
D) 25 cm
E) 35 cm
Correct Answer: C
Solution :
\[\frac{{{f}_{w}}}{{{f}_{a}}}=\frac{\mu -1}{\frac{{{\mu }_{w}}}{{{\mu }_{a}}}-1}\] \[\frac{{{f}_{w}}}{10}=\frac{1-5-1}{1/8}\] \[{{f}_{w}}=\frac{0.5\times 10}{1/8}=40\,cm\]You need to login to perform this action.
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