Correct answer =7.07 x 10-2 m
Explaination::
Given : d1=10cm =0.1 m , v1=2m/s, v2=4m/s
Solution:
by the equation of continuity , the ratio of the speed is
\(\frac{v1}{v2}=\frac{A2}{A1}=(\frac{d2}{d1})^2\)
\(\therefore \frac{d2}{d1}=\sqrt{\frac{v1}{v2}} =\sqrt{\frac{2}{4}}\) \(=\frac{1}{\sqrt2}=0.707\)
\(\therefore d2=0.707 d1\) \(=0.707(0.1m)=0.0707 m\)
=7.07 x 10-2 m