Heat energy of 735J is given to a diatomic gas allowing the gas to expand at constant pressure Each gas molecule rotates around an internal axis but do not oscillate The increase in the intemal energy of the gas will be :
Heat energy of 735J is given to a diatomic gas allowing the gas to expand at constant pressure Each gas molecule rotates around an internal axis but do not oscillate The increase in the intemal energy of the gas will be :
Show Hint
- 572J
- 735J
525J
441J
The Correct Option is C
Solution and Explanation
For a diatomic gas, the increase in internal energy is given by: \[ \Delta U = n C_V \Delta T \] where \( C_V \) is the molar heat capacity at constant volume and \( n \) is the number of moles.
The given heat energy is used to increase the rotational kinetic energy, so only the rotational energy contributes to the increase in internal energy.
For a diatomic gas, the rotational contribution is \( \frac{3}{2} \) of the total energy, so: \[ \Delta U = \frac{3}{2} \times 735 = 525 \, \text{J} \]
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Concepts Used:
Pressure
Pressure is defined as the force applied perpendicular to the surface of an object per unit area over which that force is distributed.
Everyday examples of pressure are:
- The working of the vacuum cleaner is an example of pressure. The fan inside the vacuum creates a low-pressure region which makes it easy to suck the dust particles inside the vacuum.
- Using a knife for cutting is another example of pressure. The area exposed from the knife is small but the pressure is high enough to cut the vegetables and fruits.
Formula:
When a force of ‘F’ Newton is applied perpendicularly to a surface area ‘A’, then the pressure exerted on the surface by the force is equal to the ratio of F to A. The formula for pressure (P) is:
P = F / A
Units of Pressure:
The SI unit of pressure is the pascal (Pa)
A pascal can be defined as a force of one newton applied over a surface area of a one-meter square.