Question

The pressure due to atmosphere is $1.013\times {10}^{5}Pa$. Find the force exerted by the atmosphere on the top surface of a table $2m$ long and $1m$ wide.
$$\begin{array}{rl}& A.2.026\times {10}^{5}N\\ & B.2.026\times {10}^{6}N\\ & C.2.026\times {10}^{7}N\\ & D.2.026\times {10}^{8}N\end{array}$$

Answer 1

Hint: We know that pressure is the force applied per unit area of the surface. Here, the dimensions of the table are given then we can find the area of the table. The pressure on the table is also given, then substituting the values, we can find the force on the table.

Formula used: $pressure={\displaystyle \frac{F}{A}}$

Complete step by step answer:
We know that gases exert pressure on the walls of the containers, that they are stored. Since the earth’s atmosphere also has a mixture of gases, clearly it also exerts some force per unit area of the surface. This is termed as pressure.
As pressure is defined as force per unit area, i.e.$pressure={\displaystyle \frac{F}{A}}$ then its units is given as$N/m^2$.
Given that the pressure due to atmosphere is $1.013\times {10}^{5}Pa$ acts on a table of dimension $2m$ long and $1m$ wide, clearly the length of the table is given as $l=2m$ and the breadth of the table is given as $b=1m$
Then the total area of the table is given as $A=lb=2\times 1=2m^2$
Substituting the values, we get $1.013\times {10}^5={\displaystyle \frac{F}{2}}$
Rearranging we get,
$⟹F=1.013\times {10}^5\times 2=2.026\times {10}^{5}N$
We get that $F=2.026\times {10}^{5}N$

So, the correct answer is “Option A”.

Additional Information: Atmospheric pressure is measured using a barometer, and is also known as the barometric pressure. It is the measure of the pressure exerted by the atmosphere on the earth surface.

Note: This is a very simple and straightforward sum. It doesn’t involve many calculations either. However, students are supposed to know and remember the basic formula used here. Also remember that pressure is measured in terms of atm, Pascal or mmHg.