Question

The pressure in a water pipe on the second floor of a building is 60,000 Pa, and on the third floor it is 30,000 Pa. Find the height of the second floor. (Density of water $=1000kg{m}^{-3},g=10m{s}^{-2})$.

• A. 3 m
• B. 4 m
• C. 5 m
• D. 6 m

Answer 1

The correct option is A 3 m

Second floor :
$P_1=60,000Pa,g=10m{s}^{-2}$
$P_1=h_{1}dg$

$60,000=h_1\times 1000\times 10$

$h_1=\frac{60,000}{1000\times 10}=6m$

[where $h_1=$ height of water tank above second floor]

Third floor :
$P_2=30,000Pa,g=10m{s}^{-2}$,

$\therefore 30,000=h_2\times 1000\times 19$

$\Rightarrow h_2=\frac{30000}{1000\times 10}=3m$

[where $h_2=$ height of water tank above first floor]

$\therefore$ height of the second floor
$=h_1-h_2=6m-3m=3m$