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This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 1851. |
What is the enthalpy change of 10^oC system if the heat capacity of air at 20^oC is 5 J/^oC and heat capacity of water vapor at 20^oC is 15 J/^oC, enthalpy of vaporization is 10 J, and the humidity is 40%?(a) 58 J(b) 84 J(c) 114 J(d) 135 J |
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Answer» Right option is (c) 114 J The explanation: ∆H = 5(20 – 10) + 0.4*[15(20 – 10) + 10] = 50 + 64 = 114 J. |
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| 1852. |
What is the humid heat of a mixture of air (CP = 10 J) with water vapor (CP = 15 J), if the humidity is 40%?(a) 16 J(b) 20 J(c) 24 J(d) 32 J |
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Answer» Right answer is (a) 16 J The best explanation: CS = 10 + 15*0.4 = 16 J. |
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| 1853. |
What is the humid heat of a mixture of air (CP = 20 J) with water vapor (CP = 30 J), if the humidity is 40%?(a) 24 J(b) 32 J(c) 38 J(d) 44 J |
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Answer» Right choice is (b) 32 J Easiest explanation: CS = 20 + 30*0.4 = 32 J. |
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| 1854. |
What is the humid heat of a mixture of air (CP = 10 J) with water vapor (CP = 20 J), if the humidity is 25%?(a) 10 J(b) 15 J(c) 20 J(d) 25 J |
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Answer» Right option is (b) 15 J The explanation: CS = 10 + 20*0.25 = 15 J. |
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| 1855. |
What is the degree of freedom of a mixture composed of liquid O2, gaseous H2 and ice?(a) 1(b) 2(c) 3(d) 4 |
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Answer» Right choice is (a) 1 Explanation: F = 2 – 3 + 2 = 1. |
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| 1856. |
What is the degree of freedom of a mixture composed Liquid H2O, solid Br2 and gaseous CO2, NO2?(a) 1(b) 2(c) 3(d) 4 |
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Answer» Correct choice is (c) 3 Easiest explanation: F = 2 – 3 + 4 = 3. |
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| 1857. |
CP-T curve of H2 forms a rectangle of height 20 J/^oC from 4^oC to 5^oC?(a) 20 J(b) 80 J(c) 100 J(d) 140 J |
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Answer» Correct option is (c) 100 J For explanation: Enthalpy change is the area covered under CP-T curve = Area of rectangle = 20*(5 – 4) = 20 J. |
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| 1858. |
Enthalpy of air is 15 J and enthalpy of water vapor is 20 J, if the total enthalpy of the system is 20 J, what is the humidity of the system?(a) 25%(b) 50%(c) 75%(d) 100% |
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Answer» Right answer is (a) 25% The best I can explain: 20 = 15 + 20*H, => H = 0.25 = 25%. |
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| 1859. |
What is the enthalpy change of the mixture if the enthalpy change of air is 10 J, enthalpy change of water vapor is 15 J, and the humidity is 40%?(a) 10 J(b) 12 J(c) 14 J(d) 16 J |
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Answer» Correct answer is (d) 16 J To explain I would say: ∆H = ∆Hair + ∆Hwater(h) = 10 + 15*0.4 = 16 J. |
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| 1860. |
What is the humid heat of a mixture of air (CP = 10 J) with water vapor (CP = 25 J), if the humidity is 20%?(a) 15 J(b) 20 J(c) 25 J(d) 30 J |
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Answer» The correct option is (a) 15 J Explanation: CS = 10 + 25*0.2 = 15 J. |
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| 1861. |
What is the degree of freedom of a gaseous mixture composed of CH4, CO2, H2CO3, H2O and H2O2?(a) 1(b) 2(c) 3(d) 4 |
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Answer» Right option is (d) 4 Easiest explanation: F = 2 – 1 + 3 = 4. |
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| 1862. |
A mixture contains 20% NaCl, 30% CH4 and 50% H2O, what is the mass percent of NaCl?(a) 21(b) 34(c) 45(d) 68 |
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Answer» Right answer is (b) 34 Best explanation: Mass percent of NaCl = 20*35.5/[20*35.5 + 30*16 + 50*18] = 34%. |
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| 1863. |
Enthalpy of air is 10 J and enthalpy of water vapor is 15 J, if the total enthalpy of the system is 25 J, what is the humidity of the system?(a) 20%(b) 50%(c) 100%(d) 180% |
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Answer» Correct option is (c) 100% To elaborate: 25 = 10 + 15*H, => H = 1, => H = 100%. |
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| 1864. |
Enthalpy of air is 5 J and enthalpy of water vapor is 10 J, if the total enthalpy of the system is 25 J, what is the humidity of the system?(a) 50%(b) 100%(c) 150%(d) 200% |
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Answer» Right option is (d) 200% The explanation: 25 = 5 + 10*H, => H = 2, => H = 200%. |
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| 1865. |
CP-T curve of CO2 forms a rectangle of height 10 J/^oC from 5^oC to 10^oC?(a) 10 J(b) 50 J(c) 100 J(d) 250 J |
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Answer» The correct option is (b) 50 J To elaborate: Enthalpy change is the area covered under CP-T curve = Area of rectangle = 10*(10 – 5) = 50 J. |
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| 1866. |
A mixture contains 10 grams each of CH4, H2O, and SO2, what is the mole fraction of CH4?(a) 0.14(b) 0.31(c) 0.46(d) 0.67 |
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Answer» The correct choice is (c) 0.46 To elaborate: Mole fraction of CH4 = (10/16)/[(10/16) + (10/18) + (10/64)] = 0.46. |
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| 1867. |
What is the heat transferred for an unsteady state closed system, if change in enthalpy is 15 J, and change in volume is 2 m^3 at constant pressure 5 Pa?(a) 10 J(b) 15 J(c) 20 J(d) 25 J |
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Answer» Right choice is (d) 25 J To explain: Q = 15 + 2*5 = 25 J. |
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| 1868. |
What is the partial pressure of a 10% gas in a system, if H = 2 mm Hg?(a) 0.1 mm Hg(b) 0.2 mm Hg(c) 0.3 mm Hg(d) 0.4 mm Hg |
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Answer» The correct answer is (b) 0.2 mm Hg The explanation is: p = 0.1*2 = 0.2 mm Hg. |
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| 1869. |
A 40% gas in a system has partial pressure 4 atm, what is Henry’s constant?(a) 1.6 atm(b) 4 atm(c) 10 atm(d) 16 atm |
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Answer» The correct choice is (c) 10 atm To explain: H = 4/0.4 = 10 atm. |
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| 1870. |
What is the work done by saturated water which evaporates to 20 kPa atmosphere to form 1.5 m^3 of water vapor?(a) 20 kJ(b) -20 kJ(c) 30 kJ(d) -30 kJ |
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Answer» Right option is (d) -30 kJ Easy explanation: Work done = -p∆V = -20*1.5 = -30 kJ. |
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| 1871. |
What is the work done by saturated water which evaporates to 10 kPa atmosphere to form 1 m^3 of water vapor?(a) 1 kJ(b) -1 kJ(c) 10 kJ(d) -10 kJ |
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Answer» Right option is (d) -10 kJ The explanation is: Work done = -p∆V = -10*1 = -10 kJ. |
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| 1872. |
What is the molal humidity of a gas with pressure of gas vapor 10 mm Hg and pressure of vapor free gas 20 mm Hg?(a) 25%(b) 50%(c) 100%(d) 200% |
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Answer» The correct choice is (b) 50% Explanation: Molal humidity = 10/20*100 = 50%. |
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| 1873. |
CP-T curve covers 10 J from 2^oC to 10^oC, what is the enthalpy change?(a) 10 J(b) 20 J(c) 80 J(d) 100 J |
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Answer» The correct choice is (a) 10 J Easiest explanation: Enthalpy change is the area covered under CP-T curve. |
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| 1874. |
24 grams of CH4 is passed in the process in 3 minutes, what is the molar flow rate?(a) 0.1 mole/min(b) 0.3 mole/min(c) 0.5 mole/min(d) 0.7 mole/min |
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Answer» The correct option is (c) 0.5 mole/min The explanation is: Flow rate of fluid = (24/16)/3 = 0.5 mole/min. |
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| 1875. |
Total energy of the universe is always ______(a) Increasing(b) Decreasing(c) Constant(d) Cannot say |
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Answer» Correct option is (c) Constant Easiest explanation: According to the law of conservation of energy, the total energy of the universe is always constant. |
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| 1876. |
What is the heat transferred for a 10 mole unsteady state closed system, if initial internal energy is 6 J/mole and final internal energy is 10 J/mole?(a) 4 J(b) 10 J(c) 40 J(d) 60 J |
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Answer» Right answer is (c) 40 J To explain I would say: Q = Uf – Ui = 10(10 – 6) = 40 J. |
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| 1877. |
What is the fraction of a gas in a system with partial pressure 10 mm Hg, H = 25 mm Hg?(a) 0.1(b) 0.2(c) 0.3(d) 0.4 |
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Answer» Right answer is (d) 0.4 Easiest explanation: Fraction of a gas = 10/25 = 0.4. |
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| 1878. |
What is the work done by 0.5 m^3 saturated ethanol which evaporates to 20 kPa atmosphere to form 2 m^3 of water vapor?(a) 20 kJ(b) -20 kJ(c) 30 kJ(d) -30 kJ |
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Answer» Right option is (d) -30 kJ Easy explanation: Work done = -p∆V = -20*(2 – 0.5) = -30 kJ. |
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| 1879. |
What is the molal humidity of a gas with partial pressure with vapor 1 mm Hg and partial pressure without vapor 1 atm?(a) 90%(b) 131%(c) 214%(d) 288% |
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Answer» The correct choice is (b) 131% The best I can explain: Molal humidity = 133.3/101.3*100 = 131%. |
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| 1880. |
What is the enthalpy of the reaction from 50^oC to 52^oC if CP = 15 J/^oC, and the reference enthalpy is 25 J?(a) 10 J(b) 35 J(c) 55 J(d) 65 J |
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Answer» Right choice is (c) 55 J To explain: Enthalpy of reaction = 25 + 50∫^5215.dT = 25 + 2*15 = 55 J. |
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| 1881. |
A stone has initial potential and kinetic energy as 10 J and 5 J respectively if the final potential energy of the stone is 15 J what is its final kinetic energy?(a) 0(b) 5 J(c) 10 J(d) 15 J |
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Answer» Correct answer is (a) 0 For explanation: Law of conservation of energy, 10 + 5 = 15 + KE, => KE = 0. |
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| 1882. |
What is the mass flow rate of a liquid flowing through a pipe of which 100 grams of water was collected in 10 seconds?(a) 0.01 kg/s(b) 0.05 kg/s(c) 0.1 kg/s(d) 0.5 kg/s |
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Answer» Correct choice is (a) 0.01 kg/s The best explanation: mass flow rate = 0.1/ 10 = 0.01 kg/s. |
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| 1883. |
What is the fraction of a gas in a system at partial pressure 1 mm Hg, if the 0.2 fraction of the same gas is at partial pressure 2 mm Hg and 0.3 fraction at partial pressure 3 mm Hg (Use Freundlich Isotherm)?(a) 0.1(b) 0.2(c) 0.3(d) 0.4 |
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Answer» Correct choice is (a) 0.1 For explanation: y1/y2 = (p1/p2)^n, => 0.2/0.3 = (2/3)^n => n = 1, => 0.2 = k*2^1 = k = 0.1, => y = 0.1*1^1 = 0.1. |
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| 1884. |
10 KPa of water vapor at 27^oC is saturated with air in a system, what is the mole fraction of air?(a) 0.21(b) 0.46(c) 0.79(d) 0.91 |
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Answer» Correct choice is (d) 0.91 Explanation: Fraction of air = 101.3/(10 + 101.3) = 0.91. |
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| 1885. |
100 KPa of water vapor at 27^oC is saturated with air in a system, what is the mole fraction of air?(a) 0.230(b) 0.306(c) 0.425(d) 0.503 |
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Answer» Right answer is (d) 0.503 For explanation: Fraction of air = 101.3/(100 + 101.3) = 0.503. |
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| 1886. |
What is the fraction of gas in a system with partial pressure 2 mm Hg and vapor pressure 5 mm Hg?(a) 0.4(b) 0.5(c) 0.6(d) 0.8 |
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Answer» The correct choice is (a) 0.4 For explanation I would say: Fraction of gas = 2/5 = 0.4. |
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| 1887. |
What is the vapor pressure of 40% gas in a system with partial pressure 20 mm Hg?(a) 5 mm Hg(b) 10 mm Hg(c) 20 mm Hg(d) 50 mm Hg |
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Answer» Correct choice is (d) 50 mm Hg For explanation I would say: Vapor pressure = 20/0.4 = 50 mm Hg. |
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| 1888. |
Steam having CP = 105 J/^oC, is heated from 100^oC to 104^oC, what is the enthalpy change?(a) 210 J(b) 420 J(c) 630 J(d) 840 J |
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Answer» Right choice is (b) 420 J The best I can explain: ∆H = 100∫^104105.dT = 105*4 = 420 J. |
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| 1889. |
What is the kinetic energy of an object of mass 10 Kg moving with velocity 2 m/s?(a) 10 J(b) 20 J(c) 40 J(d) 50 J |
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Answer» Right answer is (b) 20 J The best explanation: KE = ½*10*2^2 = 20 J. |
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| 1890. |
What is the specific kinetic energy of a fluid flowing at rate 0.1 m^3/s and 1 m diameter pipe?(a) 0.008 J/Kg(b) 0.016 J/Kg(c) 0.028 J/Kg(d) 0.064 J/Kg |
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Answer» Right answer is (a) 0.008 J/Kg The best explanation: v = 0.1/∏(0.5)^2, => specific KE = v^2/2 = 0.008 J/Kg. |
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| 1891. |
A material’s mass is given by the equation, m = 32P^0.02/T^0.5, where T is in Kelvin, m is in Kg and P is in mm Hg, what is the mass of material at 127^oC, use A = 10, B = 6 X 10^3 and C = 0?(a) 1.44 Kg(b) 1.69 Kg(c) 1.96 Kg(d) 2.25 Kg |
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Answer» Right option is (a) 1.44 Kg Explanation: ln p* = A – B/(C + T) = 10 – 6 X 10^3/(400) = -5, => p = 0.0067 mm Hg, => m = 32*(0.0067)^0.02/400^0.5 = 1.44 Kg. |
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| 1892. |
Pressure of a gas at 127^oC is 10 mm Hg and the pressure at 527^oC is 20 Pa, what is the value of B?(a) 225.1(b) 365.5(c) 499.2(d) 554.5 |
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Answer» Correct answer is (d) 554.5 Best explanation: ln 10/20 = B (1/800 – 1/400), => B = 554.5. |
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| 1893. |
The partial pressure of a system at 49^oC is 125 mm Hg and saturated ammonia vapor has partial pressure 20 mm Hg at 49^oC, what is the fraction of ammonia vapor in the system?(a) 0.04(b) 0.08(c) 0.16(d) 0.24 |
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Answer» Correct choice is (c) 0.16 Explanation: Fraction of ammonia vapor = 20/125 = 0.16. |
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| 1894. |
What is the pressure of a gas at T = 227^oC, it is given that A = 5, B = 4 X 104 and C = 0 if T is in kelvin and p in mm Hg?(a) 0.024 mm Hg(b) 0.049 mm Hg(c) 0.075 mm Hg(d) 0.096 mm Hg |
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Answer» The correct option is (b) 0.049 mm Hg To explain: ln p* = A – B/(C + T), => ln p = 5 – 4 X 10^3/(273 +227) = -3, => p = 0.049 mm Hg. |
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| 1895. |
A stone is released from a cliff and comes down, what is the change in kinetic energy of stone?(a) Positive(b) Negative(c) Zero(d) Cannot say |
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Answer» The correct choice is (a) Positive The best explanation: Since its velocity increases as it comes down, so a change in kinetic energy is positive. |
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| 1896. |
Which of the following statement is true?(a) Casting is the replica of the object to be cast(b) Pattern is the replica of the casting object(c) Casting and the pattern are same things(d) Molten material is casted into the casting cavity |
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Answer» Right choice is (b) Pattern is the replica of the casting object Explanation: Pattern is the replica of the object. Except for the core prints and allowances, the pattern exactly resembles the casting. |
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| 1897. |
A fluid is supplied to a cliff 20 m high and comes down by 5 m, what is the change in specific potential energy of fluid?(a) 100 J/Kg(b) 150 J/Kg(c) 200 J/Kg(d) 250 J/Kg |
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Answer» Right choice is (b) 150 J/Kg For explanation: Change in specific potential energy = 10*(20 – 5) = 150 J/Kg. |
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| 1898. |
A ball is thrown up and someone catches it on the cliff, what is the change in potential energy?(a) Positive(b) Negative(c) Zero(d) Cannot say |
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Answer» Correct answer is (a) Positive To explain I would say: Change in potential energy will be positive as the change in kinetic energy will be negative. |
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| 1899. |
A fluid in supplied to a cliff 10 m high, what is the change in specific potential energy of fluid?(a) 10 J/Kg(b) 100 J/Kg(c) 200 J/Kg(d) 500 J/Kg |
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Answer» The correct answer is (b) 100 J/Kg The best I can explain: Change in specific potential energy = 10*10 = 100 J/Kg. |
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| 1900. |
In a reactor two stream are entering, one with N2 at 10 atm and 27^oC, and another with O2 at 10 atm and 0^oC, producing NO, NO2, NO3, and O2 at 10 atm and 23^oC, what are the total degrees of freedom?(a) 12(b) 17(c) 19(d) 21 |
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Answer» Correct option is (c) 19 Easy explanation: Total species = 1 + 1 + 4 = 6, total stream flows = 3, stream pressures = 3, stream temperatures = 3, heat released = 1, and extent of reaction = 3, => degrees of freedom = 6 + 3 + 3 + 3 + 1 + 3 = 19. |
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