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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.
| 251. |
The reciprocity theorem states that (Where symbols have their usual meanings) |
| A. | F 12 = F 21 |
| B. | A 1 F 12 = A 2 F 21 |
| C. | A 1 F 21 = A 2 F 12 |
| D. | A 2 F 21 = A 1 F 12 |
| Answer» C. A 1 F 21 = A 2 F 12 | |
| 252. |
Which one of the following is not extremely inert to thermal radiation? |
| A. | Orgon |
| B. | Oxygen |
| C. | Methane |
| D. | Nitrogen |
| Answer» D. Nitrogen | |
| 253. |
A body at 500 K cools by radiating heat to ambient atmosphere maintained at 300 K. When the body has cooled to 400 K, the cooling rate as a percentage of original rate is about |
| A. | 31.1 |
| B. | 41.5 |
| C. | 50.3 |
| D. | 80.4 |
| Answer» B. 41.5 | |
| 254. |
The interchange factor is also known as |
| A. | Equivalent emissivity |
| B. | Irradiation |
| C. | Radiosity |
| D. | Shape factor |
| Answer» B. Irradiation | |
| 255. |
Consider radiant heat exchange between two non-black parallel surfaces. The surface 1 emits radiant energy E 1 which strikes the surface 2. Identify the correct option |
| A. | The value of B is α E1 |
| B. | The value of C is (1 – α1) E 1 |
| C. | The value of D is (1 – α1) (1 – α2)² E 1 |
| D. | The value of E is (1 – α1)² (1 – α2) E 1 |
| Answer» D. The value of E is (1 – α1)² (1 – α2) E 1 | |
| 256. |
What is the value of solar absorptivity for aluminum foil? |
| A. | 0.15 |
| B. | 0.16 |
| C. | 0.17 |
| D. | 0.18 |
| Answer» B. 0.16 | |
| 257. |
Choose the false statement |
| A. | Snow is nearly black to thermal radiation |
| B. | Absorption of radiation occurs in a very thin layer of material n ear the surface |
| C. | Transmissivity varies with wavelength of incident radiation |
| D. | Most of the engineering materials have rough surfaces, and these rough surfaces give regular (specular) reflections |
| Answer» E. | |
| 258. |
A small body has a total emissive power of 4.5 kW/m². Determine the wavelength of emission maximum |
| A. | 8.46 micron m |
| B. | 7.46 micron m |
| C. | 6.46 micron m |
| D. | 5.46 micron m |
| Answer» E. | |
| 259. |
Calculate the radiant flux density from a black surface at 400 degree Celsius? |
| A. | 1631.7 W/m² |
| B. | 31.7 W/m² |
| C. | 631.7 W/m² |
| D. | 11631.7 W/m² |
| Answer» E. | |
| 260. |
The distribution of radiant energy is non uniform with respect to |
| A. | Wavelength |
| B. | Direction |
| C. | Both wavelength and direction |
| D. | Time |
| Answer» D. Time | |
| 261. |
The absorptivity of a surface depends upon(i) Direction of reflected radiation(ii) Temperature of the surface(iii) CompositionIdentify the correct statements |
| A. | 1, 2 and 3 |
| B. | 1 and 3 |
| C. | 2 only |
| D. | 2 and 3 |
| Answer» E. | |
| 262. |
The net rate at which the radiation leaves the surface is given by |
| A. | e (E b – J)/1 – 4 e |
| B. | e (E b – J)/1 – 3 e |
| C. | e (E b – J)/1 – 2 e |
| D. | e (E b – J)/1 – e |
| Answer» E. | |
| 263. |
Which one is true for opaque body? |
| A. | Transmissivity is zero |
| B. | Reflectivity is zero |
| C. | Absorptivity is zero |
| D. | Reflectivity is unity |
| Answer» B. Reflectivity is zero | |
| 264. |
“Spatial distribution is also known as directional distribution”. Choose the correct option |
| A. | True |
| B. | False |
| C. | May be |
| D. | Can't say |
| Answer» B. False | |
| 265. |
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 absorption |
| A. | 236.40 W/m² |
| B. | 336.40 W/m² |
| C. | 436.40 W/m² |
| D. | 536.40 W/m² |
| Answer» D. 536.40 W/m² | |
| 266. |
What is the wavelength for visible light? |
| A. | 3.9 * 10¯¹ to 7.8 * 10¯¹ micron meter |
| B. | 4.9 * 10¯¹ to 7.8 * 10¯¹ micron meter |
| C. | 5.9 * 10¯¹ to 7.8 * 10¯¹ micron meter |
| D. | 6.9 * 10¯¹ to 7.8 * 10¯¹ micron meter |
| Answer» B. 4.9 * 10¯¹ to 7.8 * 10¯¹ micron meter | |
| 267. |
Consider a deep-space probe constructed as 1 m diameter polished aluminum sphere. Estimate the equilibrium temperature that the probe reaches if the solar energy received is 300 W/m². For solar radiation, absorptivity of aluminum is 0.3 and the average emissivity appropriate for aluminum at low temperature is 0.04 |
| A. | 415.67 K |
| B. | 315.67 K |
| C. | 215.67 K |
| D. | 115.67 K |
| Answer» C. 215.67 K | |
| 268. |
A ring (E = 0.85) of 8 cm inner and 16 cm outer diameter is placed in a horizontal plane. A small element (E = 0.7) of 1 cm² is placed concentrically 8 cm vertically below the center of the ring. The temperature of the ring is 800 K and that of small area is 400 K. Find the radiant heat gain by the small ring |
| A. | – 10.59 J/hour |
| B. | – 11.59 J/hour |
| C. | – 12.59 J/hour |
| D. | – 13.59 J/hour |
| Answer» C. – 12.59 J/hour | |
| 269. |
For a hemisphere solid angle is measured as |
| A. | Radian and its maximum value is π |
| B. | Degree and its maximum value is 180 degree |
| C. | Steradian and its maximum value is 2π |
| D. | Steradian and its maximum value is π |
| Answer» E. | |
| 270. |
What is the value of solar absorptivity for white marble? |
| A. | 0.45 |
| B. | 0.46 |
| C. | 0.47 |
| D. | 0.48 |
| Answer» C. 0.47 | |
| 271. |
What is the geometric factor for infinitely long concentric cylinders? |
| A. | 1 |
| B. | 0.5 |
| C. | 0.33 |
| D. | 0.75 |
| Answer» B. 0.5 | |
| 272. |
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 transmission |
| A. | 155.47 W/m² |
| B. | 145.47 W/m² |
| C. | 135.47 W/m² |
| D. | 125.47 W/m² |
| Answer» C. 135.47 W/m² | |
| 273. |
What is the value of fouling factor for sea water? |
| A. | 0.0001-0.0002 m² K/W |
| B. | 0.0002-0.0003 m² K/W |
| C. | 0.0003-0.0004 m² K/W |
| D. | 0.0004-0.0005 m² K/W |
| Answer» B. 0.0002-0.0003 m² K/W | |
| 274. |
What is the symbol used for dynamic viscosity? |
| A. | σ |
| B. | µ |
| C. | λ |
| D. | δ |
| Answer» C. λ | |
| 275. |
What is the wavelength band for Ultraviolet rays? |
| A. | 1 * 10¯⁶ to 3.9 * 10¯¹ micron meter |
| B. | 1 * 10¯⁴ to 3.9 * 10¯¹ micron meter |
| C. | 2 * 10¯³ to 3.9 * 10¯¹ micron meter |
| D. | 1 * 10¯² to 3.9 * 10¯¹ micron meter |
| Answer» E. | |
| 276. |
Thermal radiation strikes a surface which has a reflectivity of 0.55 and transmissivity of 0.032. A quantity known as flux is found out to be 95 W/m². Determine the rate of incident flux. |
| A. | 123.34 W/m² |
| B. | 333.37 W/m² |
| C. | 122.27 W/m² |
| D. | 227.27 W/m² |
| Answer» E. | |
| 277. |
The Planck’s constant h has the dimensions equal to |
| A. | M L² T¯¹ |
| B. | M L T¯¹ |
| C. | M L T¯² |
| D. | M L T |
| Answer» B. M L T¯¹ | |
| 278. |
Two parallel square plates, each 4 m² area, are large compared to a gap of 5 mm separating them. One plate has a temperature of 800 K and surface emissivity of 0.6, while the other has a temperature of 300 K and surface emissivity of 0.9. Find the net energy exchange by radiations between the plates |
| A. | 61.176 k W |
| B. | 51.176 k W |
| C. | 41.176 k W |
| D. | 31.176 k W |
| Answer» C. 41.176 k W | |
| 279. |
The furnace of a boiler is laid from fire clay brick with outside lagging from the plate steel, the distance between the two is quite small compared with the size of the furnace. The brick setting is at an average temperature of 365 K whilst the steel lagging is at 290 K. Calculate the radiant heat flux. Assume the following emissivity valuesFor brick = 0.85For steel = 0.65 |
| A. | 352.9 W/m² |
| B. | 452.9 W/m² |
| C. | 552.9 W/m² |
| D. | 652.9 W/m² |
| Answer» B. 452.9 W/m² | |
| 280. |
A black body of total area 0.045 m² is completely enclosed in a space bounded by 5 cm thick walls. The walls have a surface area 0.5 m² and thermal conductivity 1.07 W/ m K. If the inner surface of the enveloping wall is to be maintained at 215 degree Celsius and the outer wall surface at 30 degree Celsius, calculate the temperature of the black body |
| A. | 547.3 K |
| B. | 287.4 K |
| C. | 955.9 K |
| D. | 222.2 K |
| Answer» D. 222.2 K | |
| 281. |
The fraction of the radiative energy that is diffused from one surface element and strikes the other surface directly with no intervening reflections is called(i) Radiation shape factor(ii) Geometrical factor(iii) Configuration factorChoose the correct answer |
| A. | 1 only |
| B. | 2 only |
| C. | 1, 2 and 3 |
| D. | 3 only |
| Answer» D. 3 only | |
| 282. |
The monochromatic absorption coefficient depends upon(i) Temperature(ii) Time(iii) Pressure(iv) WavelengthIdentify the correct option |
| A. | 1, 2 and 4 |
| B. | 2, 3 and 4 |
| C. | 1 and 2 |
| D. | 1, 3 and 4 |
| Answer» E. | |
| 283. |
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/m² K, workout the reflectivity of the plate |
| A. | 0.35 |
| B. | 0.45 |
| C. | 0.55 |
| D. | 0.65 |
| Answer» C. 0.55 | |
| 284. |
A cylindrical cavity of base diameter 15 cm and height 20 cm has inside surface temperature 650 K. If emissivity of each surface is 0.85, determine the net radiative heat transfer from the cavity |
| A. | 194 W |
| B. | 184 W |
| C. | 174 W |
| D. | 164 W |
| Answer» D. 164 W | |
| 285. |
The Stefan-Boltzmann constant has units of |
| A. | kcal/m² hr K⁴ |
| B. | kcal/m hr K⁴ |
| C. | kcal/hr K⁴ |
| D. | kcal/m² K⁴ |
| Answer» B. kcal/m hr K⁴ | |
| 286. |
What is the value of solar absorptivity for polished copper? |
| A. | 0.17 |
| B. | 0.18 |
| C. | 0.19 |
| D. | 0.20 |
| Answer» C. 0.19 | |
| 287. |
What is the shape factor of a sphere of diameter d inside a cubical box of length l = d? |
| A. | π/6 |
| B. | 2 π/6 |
| C. | π/3 |
| D. | π/4 |
| Answer» B. 2 π/6 | |
| 288. |
Establish a relation for shape factor for a conical cavity with respect to itself of depth h and diameter d. The cavity is closed on its outer surface with a flat plate |
| A. | 1 – d/ (4 h² + d)^1/2 |
| B. | 1 – d/ (4 h² + d ²)^1/2 |
| C. | 1 – d/ (4 h + d²)^1/2 |
| D. | 1 – d/ (h² + d²)^1/2 |
| Answer» C. 1 – d/ (4 h + d²)^1/2 | |
| 289. |
Two long parallel surfaces, each of emissivity 0.7 are at different temperatures and accordingly have radiation exchange between them. It is desired to reduce 75% of this radiant heat transfer by inserting thin parallel shields of equal emissivity 0.7 on both sides. What should be the number of shields? |
| A. | 2 |
| B. | 4 |
| C. | 1 |
| D. | 3 |
| Answer» E. | |
| 290. |
The plane angle is defined by a region by the rays of a circle, and is measured as |
| A. | 3 L/ r |
| B. | 2 L/ r |
| C. | L/ r |
| D. | 4 L / r |
| Answer» D. 4 L / r | |
| 291. |
The solid angle is defined by a region by the rays of a sphere, and is measured as |
| A. | An/r² |
| B. | An/r |
| C. | An/r³ |
| D. | An/r⁴ |
| Answer» B. An/r | |
| 292. |
Which of the following is/are known as selective absorbers? |
| A. | Solids |
| B. | Liquids |
| C. | Gases and vapors |
| D. | Vapors |
| Answer» D. Vapors | |
| 293. |
Determine the net radiant heat exchange per m 2 area for two infinite parallel plates held at temperature of 800 K and 500 K. Take emissivity as 0.6 for the hot plate and 0.4 for the cold plate |
| A. | 6200 W/m² |
| B. | 7200 W/m² |
| C. | 8200 W/m² |
| D. | 9200 W/m² |
| Answer» B. 7200 W/m² | |
| 294. |
Which layers participated in the process of thermal radiation through solids and liquids? |
| A. | 1 micron to 1 mm thick |
| B. | 2 micron to 2 mm thick |
| C. | 1 micron to 0.5 mm thick |
| D. | 2 micron to 4.57 mm thick |
| Answer» B. 2 micron to 2 mm thick | |
| 295. |
Interchange factor for body 1 completely enclosed by body 2 (body 1 is large) is given by |
| A. | 2/ [1/E₁ + A₁/A₂ (1/E₂ – 1)]. |
| B. | 1/ [1/E₁ + A₁/A₂ (1/E₂ – 1)]. |
| C. | 4/ [1/E₁ + A₁/A₂ (1/E₂ – 1)]. |
| D. | 3/ [1/E₁ + A₁/A₂ (1/E₂ – 1)]. |
| Answer» C. 4/ [1/E₁ + A₁/A₂ (1/E₂ – 1)]. | |
| 296. |
Radiation heat transfer is characterized by |
| A. | Due to bulk fluid motion, there is transport of energy |
| B. | Thermal energy transfer as vibrational energy in the lattice structure of the material |
| C. | Movement of discrete packets of energy as electromagnetic waves |
| D. | There is circulation of fluid by buoyancy effects |
| Answer» D. There is circulation of fluid by buoyancy effects | |
| 297. |
A large plane, perfectly insulated on one face and maintained at a fixed temperature T 1 on the bare face, has an emissivity of 0.84 and loses 250 W/m² when exposed to surroundings at nearly 0 K. The radiant heat loss from another plane of the same size is 125 W/m² when bare face having emissivity 0.42 and is maintained at temperature T 2 is exposed to the same surroundings. Subsequently these two planes are brought together so that the parallel bare faces lie only 1 cm apart and the heat supply to each is so regulated that their respective temperatures T 1 and T 2 remains unchanged. Determine he net heat flux between the planes |
| A. | 0 |
| B. | 1 |
| C. | 2 |
| D. | 3 |
| Answer» B. 1 | |
| 298. |
Consider an enclosure formed by three surfaces having the following values of shape factors, emissivities and temperatures.Surface 1 i.e. curved cylindrical has an emissivity 0.75 and temperature 800 KSurface 2 i.e. closing disc has an emissivity 0.8 and temperature 700 KSurface 3 i.e. closing disc has an emissivity 0.8 and temperature 700 KThe closing flat discs are 25 mm in diameter and they have interspacing distance equal to 100 mm. If the shape factor between these two identical discs is 0.05, calculate the net rate of radiant heat flow from the curve surface to each of the closing end surface. |
| A. | 1.561 W |
| B. | 2.561 W |
| C. | 3.561 W |
| D. | 4.561 W |
| Answer» D. 4.561 W | |
| 299. |
Figure depicts the variation of which two numbers? |
| A. | Nusselt number and Reynolds number |
| B. | Stanton number and Reynolds number |
| C. | Peclet number and Grashof number |
| D. | Nusselt number and Stanton number |
| Answer» B. Stanton number and Reynolds number | |
| 300. |
Temperature of sun can be workout from |
| A. | Wein’s displacement law |
| B. | Stefan-Boltzmann law |
| C. | Kirchhoff’s law |
| D. | All of the Mentioned |
| Answer» B. Stefan-Boltzmann law | |