Physics Worksheet on Thermodynamics PDF

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Physics Worksheet on Thermodynamics There is a diatomic gas in a fixed size cubic box of side 2cm of pressure 101 kPa at temperature of 27 oC. The gas is heated until its temperature is rise to 57 oC. For diatomic particles take

𝐂𝐩 𝐂𝐯

=

𝟕 𝟓

and Avogadro’s

number𝐍𝐀 = 𝟔.𝟎𝟐 𝐱 𝟏𝟎𝟐𝟑 𝐩𝐚𝐫𝐭𝐢𝐜𝐥𝐞𝐬 𝐩𝐞𝐫 𝐦𝐨𝐥𝐞. Answer question number 1 – 4 below. Workout the following as asked by showing the necessary steps clearly.

1. What is the number of moles of the gas in the box? 2. Calculate amount heat entering to the gas in the box state its condition 3. Determine the number of particles of the gas contained in the box. 4. Does pressure in the box increased / decreased / not changed after heating process and the temperature is raised to 57 oC? Calculate the pressure if increased or decreased J 5. 68.0 g of chlorine gas (molar mass 34g/mol. Cp = 34.2J ⁄mol. K and Cv = 25.1 ⁄mol.K ) at 37oC is heated at constant pressure of 101KPa up to temperature of 87 oC. What is the no of moles of the gas? 6. Calculate volume of the gas indicated in the above question #5. 7. What is the amount of heat entering (ΔQ) into the gas of the above question #5? 8. Determine the volume of the gas in the above question #5 after it is heated and the ΔV? 9. Does work is done on the gas or by the gas (give reason) in case gas of the above question #5? Calculate work done. 10. Determine mean kinetic energy < E k > of particles of chlorine gas of the above question #5 at temperature of 37oC (Take Boltzmann constant 𝑘 = 1.38 x 10−23 J⁄K ). 11. Calculate the mean kinetic energy of particles of chlorine gas of the above question #5 at temperature of 87oC and compare the result with that of at 37oC. State reason of the change.

12. Determine the increase of internal energy (ΔU) of the gas in the above question #5. 13. If the gas in the above question #5 is heated at constant volume, calculate: i.

Work done,

ii.

Heat entering to the gas,

iii.

Increasing in internal energy of the gas.

14. What is the focus of 2 nd law of thermodynamics? 15. State 2nd law of thermodynamics. 16. What is heat engine? What it helps us? 17. Define the following terms i. Hot source

iv. Quanta

vii. Irreversible process x. Otto cycle

ii. Heat sink

v. Cyclic process

viii. Chaos

xi. Working substance

iii. Entropy

vi. Reversible process

ix. Negentropy

xii. Efficiency

18. Rewrite the statement of 2 nd law of thermodynamics for the operation of heat engine. 19. Rewrite the statement of 2 nd law of thermodynamics for the operation of refrigerators. 20. State the difference between ‘Petrol engine’ and ‘Diesel engine’. 21. Calculate efficiency and maximum theoretical efficiency of the engine based on the following schematic figure of heat engine.

Hot Source Q = 5000 KJ, T = 150,000℃ QH Determine useful work Work

QC

Cold Sink Q = 25 KJ, T = 500℃

22. Given that amount of heat released from hot source a heat engine is 10,000 J and the engine designed as 25% efficient. Calculate: (i) Useful work

(ii) Amount of heat absorbed by cold sink.

23. For an engine that operates between 4000 oC and 10,000 oC, calculate maximum theoretical efficiency of the engine. 24. What is the difference between efficiency and maximum theoretical efficiency of the engine? Give brief explanation. 25. What is refrigerator? Explain the difference between ‘Heat engine’ and refrigerator.  and 󰇍B = 4i + 2j + 5k; 󰇍 = 2i + 3j − 2k 26. Let’s given two vectors A ,  − B  and   (i). Calculate  A+ B B − A, B A− B  , B x   , B x A  and  (i). Calculate  AxB B,  Ax A A . B  x  (iii). Determine magnitudes of A,B , A B and B x A (iv). Calculate unit vector of 󰇍A and vector 󰇍B 27. Explain what you understand from the results of the above vectors operations. 28. Which of the vector operations resulted in another vector? 29. Which of the vector operations resulted in scaler? 30. What are null and unit vectors? 31. An oscillator performing SHM has sinusoidal variation of its displacement. When can it arrive at x = A 2

? That means determine time t interms of time period T at which it can reach at half of its amplitude t

t

A. Take both the timings for the oscillation of the object so use x = Asin(2π T) and x = Acos(2π ). T...