Root Mean Square Velocity of Gases

In summary, the question in the NEET Exam 2018 about the temperature at which the RMS velocity of Oxygen Molecules becomes just sufficient for escaping from the Earth's atmosphere has an incorrect mass value for the Oxygen molecule. This has been noticed by the questioner, but not by many others as the printed question remained the same in various books. Additionally, all the given options are also incorrect. It is important to note that NEET is the All Indian Medical Exam and there are negative marks for wrong answers, while unattempted questions are not marked. The questioner is unsure if they are expected to use the incorrect value provided. By equating the RMS velocity and escape velocity, the temperature obtained is that of option 2. However
  • #1
Rongeet Banerjee
45
6
Homework Statement
At what temperature will the RMS velocity of Oxygen Molecules become just sufficient for escaping from the Earth's atmosphere?
Given :
Mass of one Oxygen molecule=2.76*(10^-26)kg
Boltzmann Constant Kb=1.38*(10^-23)J/K
OPTIONS:
1. 25080 K
2. 83600 K
3. 12540 K
4. 50160 K
Relevant Equations
Vrms=√{3RT/M}=√{3KbT/m}
Escape Velocity=√{2gRe}
Re=Radius of Earth
This question came in NEET Exam 2018.Now my first query is that in the question,the mass of one Oxygen molecule is given wrong.Its exactly half it's true value.I don't think anybody has noticed this before because I couldn't find any change in the printed question on so many different books.
Also all the options are also incorrect.For anyone who is hearing about NEET for the first time, it is the All Indian Medical Exam.There are negative marks for wrong answers while unattemped questions are not marked.
What should I do?Are they expecting us to use the value which they have provided?
Then by equating Vrms and Vescape,Temperature is coming out to be that of option 2.I have no problem with the solving part but I don't know whether it will be proper to ask this horrible question in such an Awesome platform.
 
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  • #2
Rongeet Banerjee said:
Homework Statement:: At what temperature will the RMS velocity of Oxygen Molecules become just sufficient for escaping from the Earth's atmosphere?
Given :
Mass of one Oxygen molecule=2.76*(10^-26)kg
Boltzmann Constant Kb=1.38*(10^-23)J/K
OPTIONS:
1. 25080 K
2. 83600 K
3. 12540 K
4. 50160 K
Relevant Equations:: Vrms=√{3RT/M}=√{3KbT/m}
Escape Velocity=√{2gRe}
Re=Radius of Earth

This question came in NEET Exam 2018.Now my first query is that in the question,the mass of one Oxygen molecule is given wrong.Its exactly half it's true value.I don't think anybody has noticed this before because I couldn't find any change in the printed question on so many different books.
Also all the options are also incorrect.For anyone who is hearing about NEET for the first time, it is the All Indian Medical Exam.There are negative marks for wrong answers while unattemped questions are not marked.
What should I do?Are they expecting us to use the value which they have provided?
Then by equating Vrms and Vescape,Temperature is coming out to be that of option 2.I have no problem with the solving part but I don't know whether it will be proper to ask this horrible question in such an Awesome platform.
I should think few students would know that mass value was wrong. Luckily, there is no option corresponding to the correct value, so you can be sure the examiners have used the atomic weight by mistake.
I assume you are being asked by your education facility to answer this as homework. Give the expected answer, option 2. If there is the means to do so, let them and the NEET board know of the error.
 
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Likes Rongeet Banerjee

1. What is the root mean square velocity of gases?

The root mean square velocity of gases is a measure of the average speed of gas molecules in a sample. It is calculated by taking the square root of the average of the squared velocities of all the gas molecules in the sample.

2. How is the root mean square velocity of gases related to temperature?

The root mean square velocity of gases is directly proportional to the square root of the temperature of the gas. This means that as the temperature increases, the average speed of the gas molecules also increases.

3. What is the significance of the root mean square velocity of gases?

The root mean square velocity of gases is an important concept in understanding gas behavior and properties. It is used to calculate other important parameters such as pressure and kinetic energy of gas molecules.

4. How does the mass of gas molecules affect the root mean square velocity?

The root mean square velocity is inversely proportional to the square root of the mass of the gas molecules. This means that lighter gas molecules will have a higher root mean square velocity compared to heavier gas molecules at the same temperature.

5. How is the root mean square velocity of gases experimentally determined?

The root mean square velocity of gases can be experimentally determined by measuring the pressure and temperature of a gas sample and using the ideal gas law equation to calculate the root mean square velocity. It can also be measured using specialized equipment such as a gas diffusion apparatus or a gas spectrometer.

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