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MCQOPTIONS
This section includes 341 Mcqs, each offering curated multiple-choice questions to sharpen your Chemical Process Calculation knowledge and support exam preparation. Choose a topic below to get started.
| 201. |
During heat treatment, cylindrical pieces of 25 mm diameter, 30 mm height and at 30 degree Celsius are placed in a furnace at 750 degree Celsius with convective coefficient 80 W/m² degree. Find the value of biot number if thermal conductivity is 40 W/m degree |
| A. | 0.0082 |
| B. | 0.0072 |
| C. | 0.0062 |
| D. | 0.0052 |
| Answer» B. 0.0072 | |
| 202. |
An average convective heat transfer coefficient for flow of air over a sphere has been measured by observing the temperature-time history of a 12 mm diameter copper sphere (density = 9000 kg/m³ and c = 0.4 k J/kg K) exposed to air at 30 degree Celsius. The temperature of the sphere was measured by two thermocouples one located at the center and the other near the surface. The initial temperature of the ball was 75 degree Celsius and it decreased by 10 degree Celsius in 1.2 minutes. Find the heat transfer coefficient |
| A. | 27.46 W/m² K |
| B. | 21.76 W/m² K |
| C. | 29.37 W/m² K |
| D. | 25.13 W/m² K |
| Answer» E. | |
| 203. |
Which of the following dimensionless number gives an indication of the ratio of internal (conduction) resistance to the surface (convective) resistance? |
| A. | Biot number |
| B. | Fourier number |
| C. | Stanton number |
| D. | Nusselt number |
| Answer» B. Fourier number | |
| 204. |
The following data pertains to the junction of a thermocouple wire used to measure the temperature of the gas stream.Density = 8500 kg/m³, specific heat = 325 J/kg K, thermal conductivity = 40 W/m K and the heat transfer coefficient between the junction and gas = 215 W/m² K.If thermocouple junction can be approximated as 1 mm diameter sphere, determine how long it will take for the thermocouple to read 99% of the initial temperature difference. |
| A. | 9.86 seconds |
| B. | 8.86 seconds |
| C. | 7.86 seconds |
| D. | 6.86 seconds |
| Answer» B. 8.86 seconds | |
| 205. |
Which of the following is not correct in a transient flow process? |
| A. | The state of matter inside the control volume varies with time |
| B. | There can be work and heat interactions across the control volume |
| C. | There is no accumulation of energy inside the control volume |
| D. | The rate of inflow and outflow of mass are different |
| Answer» D. The rate of inflow and outflow of mass are different | |
| 206. |
What is the value of characteristics length for cube? |
| A. | L/3 |
| B. | L/4 |
| C. | L/5 |
| D. | L/6 |
| Answer» E. | |
| 207. |
Establish a relation for the shape factor of cylindrical cavity with respect to itself of depth h and diameter d. The cavity is closed on its outer surface with a flat plate |
| A. | 4 h/4 h + d |
| B. | 4 h + d/h |
| C. | 4 h + d/4 h |
| D. | h/4 h + d |
| Answer» B. 4 h + d/h | |
| 208. |
A furnace emits radiation at 2000 K. Treating it as a black body radiation, calculate the monochromatic radiant flux density at 1 micron m wavelength |
| A. | 5.81 * 10⁷ W/m² |
| B. | 4.81 * 10⁷ W/m² |
| C. | 3.81 * 10⁷ W/m² |
| D. | 2.81 * 10⁷ W/m² |
| Answer» E. | |
| 209. |
The radiant heat transfer from a plate of 2.5 cm² area at 1250 K to a very cold enclosure is 5.0 W. Determine the emissivity of the plate at this temperature |
| A. | 0.444 |
| B. | 0.344 |
| C. | 0.244 |
| D. | 0.144 |
| Answer» E. | |
| 210. |
The relationship (Wavelength)MAX T = constant, between the temperature of a black body and the wavelength at which maximum value of monochromatic emissive power occurs is known as |
| A. | Planck’s law |
| B. | Kirchhoff’s law |
| C. | Lambert’s law |
| D. | Wein’s law |
| Answer» E. | |
| 211. |
Two black discs each of diameter 50 cm are placed parallel to each other concentrically at a distance of one meter. The discs are maintained at 1000 K and 500 K. Calculate the heat flow between the discs when the disks are connected by a cylindrical black no-flux surface |
| A. | 2417.68 W |
| B. | 3417.68 W |
| C. | 4417.68 W |
| D. | 5417.68 W |
| Answer» E. | |
| 212. |
What is the symbol used for length? |
| A. | W |
| B. | M |
| C. | L |
| D. | K |
| Answer» D. K | |
| 213. |
Which one is having highest value of fouling factor? |
| A. | Sea water |
| B. | Distilled water |
| C. | Liquid gasoline |
| D. | Clean river |
| Answer» D. Clean river | |
| 214. |
The total amount of heat energy received by the sphere of radius r is |
| A. | 2 π R² S |
| B. | 6 π R² S |
| C. | 4 π R² S |
| D. | π R² S |
| Answer» D. π R² S | |
| 215. |
What is the symbol used for thermal conductivity? |
| A. | v |
| B. | g |
| C. | h |
| D. | k |
| Answer» E. | |
| 216. |
Consider two bodies, one absolutely back and the other non-black and let these be at same temperature. Which one of the following statement is correct? |
| A. | Black body radiates less intensively than a non-black body |
| B. | Non-black body radiates less intensively than a black body |
| C. | Both will radiates equally |
| D. | None of them will radiates |
| Answer» C. Both will radiates equally | |
| 217. |
A small body has a total emissive power of 4.5 kW/m². Determine its surface temperature of maximum emission |
| A. | 530.77 K |
| B. | 345.65 K |
| C. | 236.54 K |
| D. | 367.8 K |
| Answer» B. 345.65 K | |
| 218. |
Four identical pieces of copper painted with different colors of paints were heated to the same temperature and then left in the environment to cool. Which of the following paint will give fast cooling? |
| A. | White |
| B. | Rough |
| C. | Black |
| D. | Shining |
| Answer» D. Shining | |
| 219. |
When a gas or vapor is in the process of oxidation and combustion, it is called as |
| A. | Oxidation |
| B. | Flame |
| C. | Reduction |
| D. | Combustion |
| Answer» C. Reduction | |
| 220. |
What is the value of grey body factor for concentric cylinders? |
| A. | 3/ [1 – e 1/e 1 + 1 + 1 – e 2/e 2 (A 1/A 2)]. |
| B. | 4/ [1 – e 1/e 1 + 1 + 1 – e 2/e 2 (A 1/A 2)]. |
| C. | 1/ [1 – e 1/e 1 + 1 + 1 – e 2/e 2 (A 1/A 2)]. |
| D. | 2/ [1 – e 1/e 1 + 1 + 1 – e 2/e 2 (A 1/A 2)]. |
| Answer» D. 2/ [1 – e 1/e 1 + 1 + 1 – e 2/e 2 (A 1/A 2)]. | |
| 221. |
A thin metal plate of 4 cm diameter is suspended in atmospheric air whose temperature is 290 K. This plate attains a temperature of 295 K when one of its face receives radiant energy from a heat source at the rate of 2 W. If heat transfer coefficient on both surfaces of the plate is stated to be 87.5 W/m 2 K, workout the energy lost by reflection |
| A. | 0.8 W |
| B. | 0.3 W |
| C. | 0.9 W |
| D. | 0.10 W |
| Answer» D. 0.10 W | |
| 222. |
Of the radiant energy 350W/m² incident upon a surface 250W/m² is absorbed, 60W/m² is reflected and the remainder is transmitted through the surface. Workout the value for reflectivity for the surface material |
| A. | 0.181 |
| B. | 0.171 |
| C. | 0.161 |
| D. | 0.151 |
| Answer» C. 0.161 | |
| 223. |
When a surface absorbs a certain fixed percentage of striking radiation the surface is called |
| A. | Grey body |
| B. | Black body |
| C. | White body |
| D. | Opaque body |
| Answer» B. Black body | |
| 224. |
The value of reflectivity depends upon(i) Body temperature(ii) Wavelength of reflected radiation(iii) Nature of surface of bodyIdentify the correct statement |
| A. | 1 and 2 |
| B. | 2 and 3 |
| C. | 2 only |
| D. | 1 and 3 |
| Answer» E. | |
| 225. |
Energy strikes a vertical hemispherical plate with an intensity of 640 W/m². The absorptivity is thrice the transmissivity and twice the reflectivity. Determine the rate of transmission |
| A. | 236.74 W/m² |
| B. | 116.37 W/m² |
| C. | 187.87 W/m² |
| D. | 456.09 W/m² |
| Answer» C. 187.87 W/m² | |
| 226. |
Thin glass plate is an example of |
| A. | Transparent body |
| B. | Opaque body |
| C. | Black body |
| D. | White body |
| Answer» B. Opaque body | |
| 227. |
Which one is true regarding gases? |
| A. | Reflectivity is unity |
| B. | Absorptivity is zero |
| C. | Reflectivity is zero |
| D. | Transmissivity is zero |
| Answer» D. Transmissivity is zero | |
| 228. |
Radiant energy with an intensity of 800 W/m² strikes a flat plate normally. The absorptivity is thrice the reflectivity and twice the transmissivity. Determine the rate of reflection |
| A. | 518.20 W/m² |
| B. | 418.20 W/m² |
| C. | 318.20 W/m² |
| D. | 218.20 W/m² |
| Answer» E. | |
| 229. |
With respect to incident radiation, transmissivity varies with |
| A. | Time |
| B. | Temperature |
| C. | Surface area |
| D. | Wavelength |
| Answer» E. | |
| 230. |
A body through which all the incident radiations passes, is called |
| A. | Opaque body |
| B. | Black body |
| C. | Transparent body |
| D. | White body |
| Answer» D. White body | |
| 231. |
A polished metal pipe 5 cm outside diameter and 370 K temperature at the outer surface is exposed to ambient conditions at 295 K temperature. The emissivity of the surface is 0.2 and the convection coefficient of heat transfer is 11.35 W/m² degree. Calculate the overall coefficient of heat transfer by the combined mode of convection and radiation |
| A. | 11.04 W/m² degree |
| B. | 12.04 W/m² degree |
| C. | 13.04 W/m² degree |
| D. | 14.04 W/m² degree |
| Answer» D. 14.04 W/m² degree | |
| 232. |
Transmissivity is defined as |
| A. | Fraction of total energy transmitted by the body |
| B. | Fraction of total energy reflected by the body |
| C. | Fraction of total energy absorbed by the body |
| D. | Fraction of total energy absorbed and radiated by the body |
| Answer» B. Fraction of total energy reflected by the body | |
| 233. |
Which is true regarding radiation? |
| A. | Radiation travels only in medium |
| B. | Radiation travels without any medium |
| C. | Radiation travels in medium but sometimes without medium |
| D. | Radiation travels in medium or without medium |
| Answer» E. | |
| 234. |
Radiation exchange occurs in |
| A. | Solid |
| B. | Vacuum |
| C. | Liquid |
| D. | Gas |
| Answer» C. Liquid | |
| 235. |
Energy released by a radiating surface is not continuous but is in the form of successive and separate packets of energy called |
| A. | Photons |
| B. | Protons |
| C. | Electrons |
| D. | Neutrons |
| Answer» B. Protons | |
| 236. |
Thermal radiations occur in the portion of electromagnetic spectrum between the wavelengths |
| A. | 10¯² to 10¯⁴ micron |
| B. | 10¯¹ to 10¯² micron |
| C. | 0.1 to 10² micron |
| D. | 10¯² micron onwards |
| Answer» D. 10¯² micron onwards | |
| 237. |
The electromagnetic waves are emitted as a result of(i) Vibrational movement(ii) Rotational movement(iii)Atomic or sub-atomic particles comprising the matterIdentify the correct statement |
| A. | 1 and 2 |
| B. | 2 and 3 |
| C. | 1 and 3 |
| D. | 1, 2 and 3 |
| Answer» E. | |
| 238. |
What is the absorptivity of gray body? |
| A. | Below unity |
| B. | Unity |
| C. | 2 |
| D. | 2.5 |
| Answer» B. Unity | |
| 239. |
A body that reflects all the incident thermal radiations is called a |
| A. | Opaque body |
| B. | Gases |
| C. | Black body |
| D. | Specular body |
| Answer» E. | |
| 240. |
Let 220 W/m² of radiant energy is absorbed by a convex surface, 90 W/m² is reflected and 40 W/m² is transmitted through it. What is the value of absorptivity? |
| A. | 0.72 |
| B. | 0.62 |
| C. | 0.52 |
| D. | 0.42 |
| Answer» C. 0.52 | |
| 241. |
“Radiation emitted by a black surface is a function of wavelength and temperature but is independent of direction”. Choose the correct answer |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» B. False | |
| 242. |
What is the wavelength band for cosmic rays? |
| A. | Up to 45 * 10¯⁷ micron meter |
| B. | Up to 23 * 10¯⁷ micron meter |
| C. | Up to 19 * 10¯⁷ micron meter |
| D. | Up to 4 * 10¯⁷ micron meter |
| Answer» E. | |
| 243. |
A perfectly black body |
| A. | Absorbs all the incident radiation |
| B. | Allow all the incident radiation to pass through it |
| C. | Reflects all the incident radiation |
| D. | Has its surface coated with lamp black or graphite |
| Answer» B. Allow all the incident radiation to pass through it | |
| 244. |
For a prescribed wavelength a black body radiates how much energy at the temperature of body? |
| A. | Maximum |
| B. | Minimum |
| C. | 20% |
| D. | 50% |
| Answer» B. Minimum | |
| 245. |
Electromagnetic waves strikes a hot body maintained at 900 degree Celsius which has a reflectivity of 0.66 and a transmissivity of 0.022. Let the absorbed flux be 60 W/m². Determine the rate of incident flux |
| A. | 168.67 W/m² |
| B. | 178.67 W/m² |
| C. | 188.67 W/m² |
| D. | 198.67 W/m² |
| Answer» D. 198.67 W/m² | |
| 246. |
For a grey surface |
| A. | Reflectivity equals emissivity |
| B. | Emissivity equals transmissivity |
| C. | Absorptivity equals reflectivity |
| D. | Emissivity is constant |
| Answer» E. | |
| 247. |
Absorptivity of a body is equal to its emissivity |
| A. | Under thermal equilibrium conditions |
| B. | For a polished surface |
| C. | At one particular temperature |
| D. | At shorter wavelengths |
| Answer» B. For a polished surface | |
| 248. |
Which quantity can be neglected for gases? |
| A. | Transmissivity |
| B. | Reflectivity |
| C. | Absorptivity |
| D. | None can be neglected |
| Answer» C. Absorptivity | |
| 249. |
When the incident surface is a sphere, the projection of surface normal to the line of propagation is the silhouette disk of the sphere which is a circle of the diameter of |
| A. | Parabola |
| B. | Sphere |
| C. | Triangle |
| D. | Hyperbola |
| Answer» C. Triangle | |
| 250. |
A small surface emits diffusively, and measurements indicate that the total intensity associated with emission in the normal direction I n = 6500 W/square m sr. The emitted radiation is intercepted by three surfaces. Mark calculations for intensity associated with emission |
| A. | 3500 W/m² sr |
| B. | 4500 W/m² sr |
| C. | 5500 W/m² sr |
| D. | 6500 W/m² sr |
| Answer» E. | |