Two water pipes `P` and `Q` having diameters `2 xx 10^(-2) m ` and `4 xx 10^(-2) m`, respectively, are joined in series with the main supply line of water. The velocity of water flowing in pipe `P` is

Options

A. 4 times that of Q
B. 2 times that of Q
C. `1//2` times of that Q
D. `1//4` times that of Q

Answer

A

Explanation

From equation of continuty
`A_(P)v_(P)=A_(Q)v_(Q)`
`r_(P)^(2)V_(P)=r_(Q)^(2)V_(Q)" "implies(V_(P))/(V_(Q))=((r_(Q))/(r_(P)))^(2)" "implies (V_(P))/(V_(Q))=4`