A vessel contains helium, which expands at constant pressure when 15 kJ of heat is supplied to it. The work performed (in kJ) in the expansion will be ______.
- 6 KJ
- 12 KJ
- 4 KJ
- 9 KJ
The Correct Option is D
Solution and Explanation
Correct option is A)
The first law of thermodynamics gives us the relation:
q=ΔU+w
For constant pressure process,
q=nCpΔT
ΔU=nCvΔT
\(\frac{ΔU}{q}\)=CpCv=\(\frac{1}{γ}\)
Helium is a monoatomic gas i.e γ=\(\frac{5}{3}\)
ΔU=\(\frac{1}{γ}\)q=\(\frac{3}{5}\)×15kJ=9kJ
Top Questions on Pressure
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- The volume contraction of a solid copper cube of edge length 10 cm, when subjected to a hydraulic pressure of \( 7 \times 10^6 \) Pa, would be _____ mm\(^3\). (Given bulk modulus of copper = \( 1.4 \times 10^{11} \) N m\(^{-2}\))
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- A spherical soap bubble inside an air chamber at pressure \(𝑃_0 = 10^5 \)Pa has a certain radius so that the excess pressure inside the bubble is Δ𝑃 = 144 Pa. Now, the chamber pressure is reduced to \(8𝑃_0/27\) so that the bubble radius and its excess pressure change. In this process, all the temperatures remain unchanged. Assume air to be an ideal gas and the excess pressure Δ𝑃 in both the cases to be much smaller than the chamber pressure. The new excess pressure Δ𝑃 in Pa is
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Questions Asked in JEE Main exam
Which one of the following graphs accurately represents the plot of partial pressure of CS₂ vs its mole fraction in a mixture of acetone and CS₂ at constant temperature?
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In the given figure, the blocks $A$, $B$ and $C$ weigh $4\,\text{kg}$, $6\,\text{kg}$ and $8\,\text{kg}$ respectively. The coefficient of sliding friction between any two surfaces is $0.5$. The force $\vec{F}$ required to slide the block $C$ with constant speed is ___ N.
(Given: $g = 10\,\text{m s}^{-2}$)
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$x + y + z = 6$
$2x + 5y + az = 36$
$x + 2y + 3z = b$
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Concepts Used:
Specific Heat Capacity
Specific heat of a solid or liquid is the amount of heat that raises the temperature of a unit mass of the solid through 1°C.
Molar Specific Heat:
The Molar specific heat of a solid or liquid of a material is the heat that you provide to raise the temperature of one mole of solid or liquid through 1K or 1°C.
Specific Heat at Constant Pressure or Volume:
The volume of solid remains constant when heated through a small range of temperature. This is known as specific heat at a constant volume. It is denoted as CV.
The pressure of solid remains constant when heated through a small range of temperature. This is known as specific heat at constant pressure which can be denoted as CP.