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[QUE/TH-06009] TH-PROBLEMNode id: 5204pageIn the compression stroke of a Diesel engine, air is compressed from atmospheric pressure and room temperature to about ${1\over 15}$ of its original volume. Find the final temperature, assuming a reversible adiabatic compression. |
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22-01-20 10:01:18 |
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[QUE/TH-02012] TH-PROBLEMNode id: 5203pageIn the Fig.-2, let $P_2=10\times10^5$Nm$^{-2}$, $P_1=4\times10^5$Nm$^{-2}$, $v_1=2.5$m$^3$kilomole$^{-1}$. Find
- the temperature $T$,
- the specific volume $v_2$,
- the temperature at points $b$ and $d$,
- the actual volume $V$ at point $a$ if the system consists of 4 kilomoles of hydrogen,
- the mass of hydrogen.
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22-01-20 09:01:47 |
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[QUE/TH-02011] TH-PROBLEMNode id: 5202pageFig.-2 shows five processes, $a-b,~b-c,~c-d,~d-a,~a-c$, plotted in the $P-v$ plane for an ideal gas in a closed system. Show the same processes (a) in the $P-T$ plane. (b) in the $T-v$ |
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22-01-20 09:01:44 |
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[QUE/TH-02010] TH-PROBLEMNode id: 5201pageThe $U$-tube in Fig.-1 below, of uniform cross section 1 cm$^2$, contains mercury to the depth shown. The barometric pressure is 750 Torr. The left side of the tube is now closed at the top, and the right side in connected to a good vacuum pump. Assuming that the temperature remains constant answer the following questions.
- How far does the mercury level fall in the left side?
- What is final pressure of the trapped air?
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22-01-20 09:01:18 |
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[QUE/TH-02009] TH-PROBLEMNode id: 5200pageThe table below lists corresponding values of the pressure and specific volumes of steam at three temperatures of 700$^\circ$F, 1150$^\circ$F and 1600$^\circ$F. Without converting the MKS units, compute the ratio $Pv/T$ at each temperature and pressure; and for each temperature plot theses ratios as a function of pressure. Estimate the extrapolated value of $Pv/T$ as $P$ approaches zero, and find the value of $R$ in $J$ kilomoles $K^{-1}$.
{$P$} |
{$t=700^\circ$F} |
{$t=1150^\circ$F} |
{$t=1600^\circ$F} |
\{$lb~in^{-2}$} |
{$v~ft^3~lb^{-1}$} |
{$v~ft^3~lb^{-1}$} |
{$v~ft^3~lb^{-1}$} |
500 |
1.3040 |
1.888 |
2.442 |
1000 |
0.6080 |
0.918 |
1.215 |
2000 |
0.2490 |
0.449 |
0.601 |
3000 |
0.0984 |
0.289 |
0.397 |
4000 |
0.0287 |
0.209 |
0.294 |
5000 |
0.0267 |
0.161 |
0.233 |
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371.1$^\circ$C |
621.1$^\circ$C |
871.1$^\circ$C |
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22-01-20 09:01:29 |
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[QUE/TH-02008] TH-PROBLEMNode id: 5199pageAn approximate equation of state of a real gas at moderate pressures, devised to take into account of the finite size of the molecules, is $P(v-b)=R\theta$, where $R$ and $b$ are constants. Show that
\begin{equation*} \beta = {1/\theta\over 1+bP/(R\theta)}~~,~~~~\chi = {1/P\over1+bP/(R\theta)} \end{equation*} |
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22-01-16 17:01:49 |
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[QUE/TH-02007] TH-PROBLEMNode id: 5198pageThe fundamental frequency of vibration of a wire of length $L$, mass $m$, and tension $\mathcal{J}$ is given by $$ f_1={1\over2L} \sqrt{{\mathcal{J}L\over m}} $$ With what frequency of vibration with the wire of Prob. [2] vibrate at 20$^\circ$C; $8^\circ$C? (The density of wire is $9.0\times10^3$ kg/m$^3$) |
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22-01-16 17:01:47 |
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[QUE/TH-02006] TH-PROBLEMNode id: 5197pageA metal wire of cross-sectional area 0.0085 cm$^2$ under a tension of 20 N and a temperature of 20$^\circ$C is stretched between two rigid supports 1.2 m apart. If the temperature is reduced to 8$^\circ$C, what is the final tension? (Assume that $\alpha$ and $Y$ remain constant at the values $1.5\times10^{-5}$K$^{-1}$ and $2.0\times10^9$ N/m$^2$ respectively) |
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22-01-16 17:01:07 |
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[QUE/TH-02005] TH-PROBLEMNode id: 5196pageA wire undergoes an infinitesimal change from an initial equilibrium state to a final equilibrium state, show that the change of tension is equal to $$ d\mathcal{J} = -\alpha A Y d\theta + {AY\over L} ~dL $$ |
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22-01-16 17:01:39 |
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[QUE/TH-02004] TH-PROBLEMNode id: 5195pageA metal, whose volume expansivity is 5.0$\times10^{-5}$ K$^{-1}$ and isothermal compressibility is $1.2\times10^{-11}$Pa$^{-1}$, is at a pressure of $1\times10^5$ Pa and a temperature of 20$^\circ$C. A thick surrounding cover of invar, of negligible compressibility and expansivity, fit is very snugly.
- [(a)] What will be the final pressure if the temperature is raised to 32$^\circ$C?
- [(b)] If the cover can with stand a maximum pressure of $1.2\times10^8$Pa, what is the highest temperature two which the system may be raised?
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22-01-16 17:01:17 |
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[QUE/TH-02003] TH-PROBLEMNode id: 5194pageAn approximate equation of state of a real gas at moderate pressures is given by $$ P_v = R\theta\left(1+{B\over v}\right) $$ where $R$ is a constant and $B$ is a function of $\theta$ only. Show that
- [(a)] $\beta=\dfrac{1}{\theta}\left(v+B+\theta~\dfrac{dB}{d\theta}\right)\biggl/(v+2B)$
- [(b)] $\kappa = \dfrac{1} {P} ~\dfrac{1}{(1+BR\theta/Pv^2)}$ \hfill{[7]}
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22-01-16 17:01:02 |
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[QUE/TH-02002] TH-PROBLEMNode id: 5193pageFor a gas satisfying van de Waals equation $$ \left(P+{a\over v^2}\right) (v-b) = R\theta $$ show that the critical temperature $\theta_c$, critical pressure $P_c$, and the critical volume are given by
$\theta_c = {8a\over27Rb}~,~~P_c={a\over27b^2}~,~~v_c=3b\,.\,.$
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22-01-16 17:01:29 |
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[QUE/EM-05001] EM-PROBLEMNode id: 5192pageDetermine the polarizability of to charges that are bound together by a harmonic potential with force constant \(k\). |
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22-01-16 13:01:42 |
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[QUE/EM-04013] EM-PROBLEMNode id: 2390pageA sphere of radius \(R_1\) has charge uniformly distributed throughout its volume except for a smaller charge-free spherical volume of radius \(R_2 < R_1\) located entirely within the big sphere. Show that the electric field at all points inside the small sphere is a constant.
Zangwill |
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22-01-16 07:01:25 |
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[QUE/EM-04012] EM-PROBLEMNode id: 2384page A spherical shell is cut into two hemispheres which are glued with an insulated boundary. The potentials of the hemispheres is kept at constant values \( V_0\) for \(0\lt \theta\lt \pi/2\) and at \(-V_0\) for \(\pi/2 \lt \theta \lt \pi\). Use Green function in spherical coordinates to find the potential at an arbitrary point.
RamMohan |
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22-01-16 07:01:01 |
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[QUE/EM-04005] EM-PROBLEMNode id: 2379pageA conducting spherical shell of radius \(a\) is placed in a uniform field \(vec{E}\). Show that the force tending to separate two halves of the sphere across a diametrical plane perpendicular to \(\vec{E}\) is given by \[ F = \frac{9}{4}\pi \epsilon_0a^2 E^2.\]
Panofsky and Philips |
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22-01-16 06:01:40 |
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[QUE/EM-10005] --- EM-PROBLEMNode id: 3015pageAn inductor, made up of a very long air-core solenoid of length $\ell$, radius $r$ and $n$ turns per unit length, carries a current $I$. For $\frac{dI}{dt}>0$, verify that \begin{equation} \frac{dU_B}{dt} = -\iint_S \vec{S}.\overrightarrow{dA}, \end{equation} where the surface $S$ in the surface integral in the right hand side is the surface that encloses the solenoid and \(U_B\) is the energy density associated with the magentic field.
Analysis
You need to understand the following. Read the given question several times and answer the following questions. After making sure that you have correct answers and that you understand them as well, try to solve the problem.
- What is Poynting theorem?
- What does $\vec{S}$ in \EqRef{EQ02} stand for?
- What is the expression of the Poynting vector?
- What physical quantities do the symbols $U_B$ and $\vec{S}$, in \EqRef{EQ02}, represent?
- Is it correct that the expressions for the quantities $\vec{S}$ and $U_B$ involve $\vec{E}$ and $\vec{B}$? If not, what is the correct expression?
- What field(s) does the solenoid produce? Magnetic field $\vec{B}$? Electric field $\vec{E}$? Both of these? None of these? Do you know the expressions?
- Compute the magnetic field produced by the solenoid. Write zero as your answer if it does not produce it.
- Repeat the above question for the electric field.
- Find $\vec{S}$ in terms of current $I$ and compute the surface integral $\iint_S \vec{S}.\overrightarrow{dA}$. Find $\vec{S}$ on the sutface of the solenoid.
- What will be the volume integral of $U_B$?
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22-01-15 22:01:40 |
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[QUE/TH-01006] TH-PROBLEMNode id: 5191pageIn the table below, a number in the top row represents the pressure of a gas in the bulb of a constant volume gas thermometer when the bulb is immersed in the triplet cell. The bottom row represents the corresponding readings of the pressure when the bulb is surrounded by a material at constant unknown temperature. Calculate the ideal gas temperature of this material (use five significant figures) {Zemansky}
$P_{TP}$,~ mm Hg |
1000.00 |
750.00 |
500.00 |
250.00 |
$P_{TP}$, mm Hg |
1535.30 |
1151.60 |
767.82 |
383.95 |
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Is it necessary to convert the
pressures from mm Hg to Pascal? |
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22-01-14 14:01:00 |
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[QUE/TH-01005] TH-PROBLEMNode id: 5190pageA new scale is to defined in terms of ideal gas scale of temperature. Let the difference of ice points and the steam points be fixed at $t_s-t_i=180$ deg. If $\displaystyle{\lim_{P_{TP}\to0}\left({P_s\over P_i}\right)}$ is given to be 1.3661 as the best experimental value, find $t_s$ and $t_i$ on the new scale. |
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22-01-14 14:01:30 |
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[QUE/TH-13005] TH-PROBLEMNode id: 5188pageA box of volume $2V$ is divided into equal halves by a thin partition. The left side contains perfect gas at pressure $p_L$ and the right side is vacuum. A small hole of area $A$ is punched in the partition at time $t\,=\,0$. What is the pressure in the left had side $p_L(t)$ after a time t ?. Assume the temperature to be constant on both the sides as $T$. Assume Maxwell- Boltzmann statistics. |
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22-01-14 13:01:08 |
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