Question

Two capillary of length L and 2L and of radius R and 2R are
connected in series. The net rate of flow of fluid through
them will be (given rate to the flow through single capillary,
X =πPR⁴/8????L)
(a) 8/9 X
(b) 9/8 X
(c) 5/7 X
(d) 7/5X

Answer 1

Answer:

resistance is given by R =

πr

4

8ηL

When two capillary tubes of same size are joined in parallel, then equivalent fluid resistance is

R

s

=R

1

+R

2

=

πR

4

8ηL

+

π(2R)

4

8η×2L

=(

πR

4

8ηL

)×

8

9

Rate

of flow =

R

s

P

=

8ηL

πPR

4

×

9

8

=

9

8

X[asX=

8ηL

πPR

4

]