JEE Main2017PhysicsMechanical Properties of FluidsActual
Two tubes of radii r 1 and r 2 and lengths l 1 and l 2, respectively, are connected in series and a liquid flows through each of them in stream line conditions. P 1 and P 2 are pressure differences across the two tubes. If P 2 is 4 P 1 and l 2 is l 1 4 then the radius r 2 will be equal to :
Options
- A4 r 1
- Br 1
- C2 r 1
- Dr 1 2
Correct answer
D. r 1 2
Step-by-step solution
d V d t = π 8 p r 4 η L p 1 r 1 4 L 1 = p 2 r 2 4 L 2 p 1 r 1 4 l 1 = 4 p 1 r 2 4 l 1 4 ⇒ r 2 4 = r 1 4 16 ⇒ r 2 = r 1 2