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Physics Guru is an online education and competitive examinations preparation portal founded by Manish Verma, an IIT Madras alumnus, providing learning resources for competitive examinations.

The emphasis is on conceptual understanding, analytical thinking and problem solving rather than simply memorising formulas and standard methods.

The objective is to help students understand what they are learning and develop the ability to solve problems they have not seen before.

An empty LPG cylinder weighs 14.8 kg ....

An empty LPG cylinder weighs 14.8 kg. When full, it weighs 29.0 kg and shows a pressure of 3.47 atm. In the course of use at ambient temperature, the mass of the cylinder is reduced to 23.0 kg. The final pressure inside the cylinder is _ _ _ _ atm. (Nearest integer)
(Assume LPG to be an ideal gas)

Solution

Weight of gas before use = 29.0 - 14.8 = 14.2 kg

Weight of gas after use = 23.0 - 14.8 = 8.2 kg

Now, $\frac {P_1}{n_1} = \frac {P_2}{n_2} $

$\therefore \frac {3.47}{14.2} =  \frac {P_2}{8.2} $

$\Rightarrow P_2 = \frac {3.47 \times 8.2}{14.2} \approx 2 atm $

Answer: 2