here in this example we are given that in
the figure shown the liquid in man o meter
tubes is of specific gravity zero point 9.
and if the difference in levels of the liquid
in tube is 40 centimeter we are required to
find the height difference of water level
in the two tanks.
here, we are given that . this point b and
this point ay are at a separation 40 centimeter.
and let us consider this b is located at a
depth . h 2, below the water level and, in
this container.
the point b is below a depth h-one.
from the water level.
and if we talk about , pressure at point ay
and pressure at point b. so in this situation
we can directly write, that pressure at point
ay and b are related as . pressure at point
ay, is.
say p-ay , then pressure at point p can be
given as this is the same pressure which is
at this point also.
so this can be written as plus h ro g as distance
is 40 centimeter i can write it 40 multiplied
by ro of liquid into g. this should be equal
to p-b. and pressure at ay we can calculate
from this side as, this . surface is open
to atmosphere here if it is atmospheric pressure
. then we can write down pressure at this
point will be p-atmospheric plus h 1 ro g.
minus, 40 ro g. so, in this situation, we
can write this as . pressure at ay is equal
to p-atmosphere , plus, h 1 minus 40 multiplied
by , ro of water g. that is multiplied by
1 into g . plus, 40 ro-liquid g is also given
to us so this can be written as , forty multiplied
by density of liquid is zero point 9 into
g. and this should be equal to pressure at
point b , which can be written from the other
side that is, p-atmospheric.
plus h-two multiplied by 1 into g this is
the way how we can calculate it. and if we
just relate the two parameters, here.
we can directly write, in this situation p-atmospheric
will get cancelled out . and in this expression
we can see, this h 1 g also gets cancelled
out in this expression . this h one minus
40 plus 40 multiplied by zero point 9. is
equal to h 2.
so here h 1 minus h 2 can be written as , 40
multiplied by zero point 1 that is 4 centimeter
that will be the answer to this problem.
