Selina Solutions Class 9 Physics Solutions for Exercise 4A in Chapter 4 - Chapter 4 Pressure In Fluids And Atmospheric Pressure

Question 42 Exercise 4A

(a) Calculate the height of a water column which will exert on its base the same pressure as the 70cm column of mercury. The density of mercury is $13.6 g cm^{-3}$ .

(b) Will the height of the water column in part (a) change if the cross-section of the water column is made wider?

Answer:

(a) We know that the pressure exerted by the water column, P = h ρ g

The density of water = 1

As the pressure of water and mercury is the same,

$\begin{array}{l} h_{w} \rho_{w} g=h_{m} \rho_{m} g \\ h_{w} \times 1 \times g=h_{m} \rho_{m} g \\ h_{w}=h_{m} \rho_{m} \\ \quad=\frac{70}{100} \times 13.6 \end{array}$

Height of the water column= 9.52m

(b) If the water column is made wider, the height of the water column will be unaffected.

Related Questions

Define the term thrust. State its S.I. unit.

What is meant by pressure? State its S.I. unit.

(a) What physical quantity is measured in a bar? (b) How is the unit bar related to the S.I. unit p...

Define one pascal (Pa), the S.I. unit of pressure.

State whether thrust is a scalar or vector?

State whether the pressure is a scalar or vector?

Exercises

Exercise 4A

Exercise 4B