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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.
| 101. |
When the emissivity of non-black surface is constant at all temperatures and throughout the entire range of wavelength, the surface is called |
| A. | Gray body |
| B. | Transparent body |
| C. | Opaque bodies |
| D. | Perfect black body |
| Answer» B. Transparent body | |
| 102. |
What is the unit of coefficient of radiant heat transfer? |
| A. | W/K |
| B. | W/m² K |
| C. | W/m² |
| D. | W/m K |
| Answer» C. W/m² | |
| 103. |
Radiation shield are used between the emitting surfaces such that |
| A. | To reduce overall heat transfer |
| B. | To increase overall heat transfer |
| C. | To increase density |
| D. | To reduce density |
| Answer» B. To increase overall heat transfer | |
| 104. |
The temperature of a solid surface changes from 27 K to 627 K. The emissive power changes would then confirm to the ratio |
| A. | 6:1 |
| B. | 9:1 |
| C. | 81:1 |
| D. | 27:1 |
| Answer» D. 27:1 | |
| 105. |
Engineering problems of practical interest are involved with heat exchange between two or more surfaces, and this exchange is strongly dependent upon(i) Radiative properties(ii) Temperature levels(iii) Surface geometricsIdentify the correct statements |
| A. | 1 and 2 |
| B. | 1 and 3 |
| C. | 2 and 3 |
| D. | 1, 2 and 3 |
| Answer» E. | |
| 106. |
The emissivity of the gray surface may be expressed as |
| A. | σ /2 σb |
| B. | σ / 3 σb |
| C. | σ / σb |
| D. | ½ σ / σb |
| Answer» D. ½ σ / σb | |
| 107. |
What is the symbol used for specific heat? |
| A. | C S |
| B. | C R |
| C. | C P |
| D. | C M |
| Answer» D. C M | |
| 108. |
Which of the followings is a wrong statement?The shape factor is equal to one |
| A. | For any surface completely enclosed by another surface |
| B. | For infinite parallel planes radiating only to each other |
| C. | For a flat or convex surface with respect to itself |
| D. | Inside cylinder to outer cylinder of a long co-axial cylinder |
| Answer» E. | |
| 109. |
Consider two surfaces, one absolutely black and the other non-black. These surfaces are arranged parallel to each other and so close that the radiation of one falls totally on the other. Choose the correct option |
| A. | 1 denotes the radiant energy E emitted by the non-black surface impinges on the black surface |
| B. | 1 denotes the radiant energy E emitted by the black surface impinges on the non-black surface |
| C. | 2 and 3 denotes the quantity α E b |
| D. | 4 denotes the quantity (1 – α) E b |
| Answer» B. 1 denotes the radiant energy E emitted by the black surface impinges on the non-black surface | |
| 110. |
The emissivity and the absorptivity of a real surface are equal for radiation with identical temperature and wavelength. This law is referred to as |
| A. | Kirchhoff’s law |
| B. | Lambert’s law |
| C. | Planck’s law |
| D. | Wein’s displacement law |
| Answer» B. Lambert’s law | |
| 111. |
What is the symbol used for mass? |
| A. | M |
| B. | L |
| C. | A |
| D. | V |
| Answer» B. L | |
| 112. |
A surface for which emissivity is constant at all temperatures and throughout the entire range of wavelength is called |
| A. | Opaque |
| B. | Grey |
| C. | Specular |
| D. | Diathermanous |
| Answer» C. Specular | |
| 113. |
When Stefan-Boltzmann law is applied to a black body, it takes the form |
| A. | E = σ T |
| B. | E = σ T² |
| C. | E = σ T³ |
| D. | E = σ T⁴ |
| Answer» E. | |
| 114. |
What is the symbol used for kinematic viscosity? |
| A. | v |
| B. | λ |
| C. | µ |
| D. | σ |
| Answer» B. λ | |
| 115. |
Determine the radiant heat flux between two closely spaced, black parallel plates radiating only to each other if their temperatures are 850 K and 425 K. The plates have an area of 4 m² |
| A. | .040 |
| B. | .030 |
| C. | .020 |
| D. | .010 |
| Answer» E. | |
| 116. |
What is the value of fouling factor for clean river? |
| A. | 0.0014-0.0018 m² K/W |
| B. | 0.0010-0.0014 m² K/W |
| C. | 0.0006-0.0010 m² K/W |
| D. | 0.0002-0.0006 m² K/W |
| Answer» E. | |
| 117. |
A radiation shield should |
| A. | Have high transmissivity |
| B. | Absorb all the radiations |
| C. | Have high reflexive power |
| D. | Partly absorb and partly transmit the incident radiation |
| Answer» D. Partly absorb and partly transmit the incident radiation | |
| 118. |
What is the geometric factor for concentric spheres? |
| A. | 0.85 |
| B. | 0.33 |
| C. | 1 |
| D. | 0.95 |
| Answer» D. 0.95 | |
| 119. |
A 100 W light bulb has a tungsten filament (emissivity = 0.30) which is required to operate at 2780 K. If the bulb is completely evacuated, calculate the minimum surface area of the tungsten filament |
| A. | 0.98 * 10¯⁴ m² |
| B. | 1.98 * 10¯⁴ m² |
| C. | 2.98 * 10¯⁴ m² |
| D. | 3.98 * 10¯⁴ m² |
| Answer» B. 1.98 * 10¯⁴ m² | |
| 120. |
Which one of the following is true for opaque non-black surface? |
| A. | J = E +2 p G |
| B. | J = E + p G |
| C. | J = 2 E + p G |
| D. | J = ½ E + p G |
| Answer» C. J = 2 E + p G | |
| 121. |
The absorptivity of black body equals to |
| A. | 2 |
| B. | 1 |
| C. | 3 |
| D. | 4 |
| Answer» C. 3 | |
| 122. |
The energy radiated out decreases with increases in α and becomes zero at an angle of |
| A. | 45 |
| B. | 30 |
| C. | 0 |
| D. | 90 |
| Answer» E. | |
| 123. |
What is the symbol used for gravity? |
| A. | g |
| B. | h |
| C. | k |
| D. | v |
| Answer» B. h | |
| 124. |
A conical 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. | 168.3 W |
| B. | 158.3 W |
| C. | 148.3 W |
| D. | 138.3 W |
| Answer» B. 158.3 W | |
| 125. |
What is the value of solar absorptivity for asphalt? |
| A. | 0.90 |
| B. | 0.80 |
| C. | 0.70 |
| D. | 0.60 |
| Answer» B. 0.80 | |
| 126. |
What is the value of fouling factor for treated boiler feed 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 | |
| 127. |
Which of the following can be used as a radiating shield? |
| A. | Carbon |
| B. | Thin sheets of aluminum |
| C. | Iron |
| D. | Gold |
| Answer» C. Iron | |
| 128. |
What is the symbol used for coefficient of volumetric expansion? |
| A. | λ |
| B. | µ |
| C. | δ |
| D. | β |
| Answer» E. | |
| 129. |
The value of solar constant varies between |
| A. | 1123 and 1237 W/m² |
| B. | 1345 and 1453 W/m² |
| C. | 1987 and 2346 W/m² |
| D. | 1335 and 1815 W/m² |
| Answer» E. | |
| 130. |
The solar radiation that is felt at the earth’s surface includes(i) Direct radiation that has passed through the atmosphere(ii) Diffuse radiation from the sky(iii) Absorbed radiation from the waterIdentify the correct statement |
| A. | 1 only |
| B. | 1 and 2 |
| C. | 1, 2 and 3 |
| D. | 2 and 3 |
| Answer» C. 1, 2 and 3 | |
| 131. |
Two opposed, parallel, infinite planes are maintained at 420 K and 480 K. Calculate the net heat flux between these planes if one has an emissivity of 0.8 and other an emissivity of 0.7 |
| A. | 534.86 W/m² |
| B. | 634.86 W/m² |
| C. | 734.86 W/m² |
| D. | 834.86 W/m² |
| Answer» D. 834.86 W/m² | |
| 132. |
The total radiant energy leaving a surface per unit time per unit surface area is represented by |
| A. | Radiation |
| B. | Radiosity |
| C. | Irradiation |
| D. | Interchange factor |
| Answer» C. Irradiation | |
| 133. |
Two radiating surface A 1 = 6 m² and A 2 = 4 m² have shape factor F 12 = 0.1. Then the shape factor F 21 will be |
| A. | 0.12 |
| B. | 0.18 |
| C. | 0.15 |
| D. | 0.10 |
| Answer» D. 0.10 | |
| 134. |
What is the value of fouling factor for oil bearing steam? |
| A. | 0.0002 m² K/W |
| B. | 0.0003 m² K/W |
| C. | 0.0004 m² K/W |
| D. | 0.0005 m² K/W |
| Answer» B. 0.0003 m² K/W | |
| 135. |
In the given diagram let r be the length of the line of propagation between the radiating and the incident surfaces. What is the value of solid angle W? |
| A. | A sin α |
| B. | A cos α |
| C. | 2A cos α |
| D. | 2A cos α |
| Answer» C. 2A cos α | |
| 136. |
What is the shape factor for a hemispherical bowl with respect to itself of diameter d? The cavity is closed on its outer surface with a flat plate |
| A. | 1.5 |
| B. | 1 |
| C. | 0.5 |
| D. | 2.5 |
| Answer» D. 2.5 | |
| 137. |
The total emissive power of the emitter with area d A and temperature T is given by |
| A. | E = 2 σ T⁴ d A |
| B. | E = 3 σ T⁴ d A |
| C. | E = σ T⁴ d A |
| D. | E = ½ σ T⁴ d A |
| Answer» D. E = ½ σ T⁴ d A | |
| 138. |
The intensity of normal radiation In is how much times the emissive power? |
| A. | 1/π |
| B. | 2/ π |
| C. | 3/ π |
| D. | 4/ π |
| Answer» B. 2/ π | |
| 139. |
A diathermanous body |
| A. | Shines as a result of incident radiation |
| B. | Gets heated up a result of absorption of incident radiation |
| C. | Allows all the incident radiation to pass through it |
| D. | Partly absorbs and partly reflects the incident radiation |
| Answer» D. Partly absorbs and partly reflects the incident radiation | |
| 140. |
If two surfaces are at the same temperature, then the conditions correspond to mobile thermal equilibrium for which the resultant interchange of heat is zero are |
| A. | 3 E – α EB = 0 |
| B. | 2 E – α EB = 0 |
| C. | E – α EB = 0 |
| D. | ½ E – α EB = 0 |
| Answer» D. ½ E – α EB = 0 | |
| 141. |
An enclosure consists of four surfaces 1, 2, 3 and 4. The view factors for radiation heat transfers areF 11 = 0.1F 12 = 0.4F 13 = 0.25The surface areas A 1 and A 2 are 4 m² and 2 m². The view factor F 41 is |
| A. | 0.50 |
| B. | 0.75 |
| C. | 0.1 |
| D. | 0.25 |
| Answer» B. 0.75 | |
| 142. |
The quantity h L C/k is known as |
| A. | Biot number |
| B. | Fourier number |
| C. | Stanton number |
| D. | Nusselt number |
| Answer» B. Fourier number | |
| 143. |
A cylindrical stainless steel (k = 25 W/m K) ingot, 10 cm in diameter and 25 cm long, passes through a heat treatment furnace which is 5 meter in length. The initial ingot temperature is 90 degree Celsius, the furnace gas is at 1260 degree Celsius and the combined radiant and convective surface coefficient is 100 W/m² K. Determine the maximum speed with which the ingot moves through the furnace if it must attain 830 degree Celsius temperature. Take thermal diffusivity as 0.45 * 10¯⁵ m²/s |
| A. | . 000116 m/s |
| B. | .000216 m/s |
| C. | . 000316 m/s |
| D. | . 000416 m/s |
| Answer» C. . 000316 m/s | |
| 144. |
Identify the correct relation between Biot number and Fourier number |
| A. | 4 b T = B I F 0 |
| B. | 2 b T = B I F 0 |
| C. | 3 b T = B I F 0 |
| D. | b T = B I F 0 |
| Answer» E. | |
| 145. |
What is the wavelength band for TV rays? |
| A. | 1 * 10³ to 34 * 10¹⁰ micron meter |
| B. | 1 * 10³ to 2 * 10 ¹⁰ micron meter |
| C. | 1 * 10³ to 3 * 10¹⁰ micron meter |
| D. | 1 * 10³ to 56 * 10¹⁰ micron meter |
| Answer» C. 1 * 10³ to 3 * 10¹⁰ micron meter | |
| 146. |
What is the criterion for the applicability of lump system analysis? |
| A. | Mean length |
| B. | Normal length |
| C. | Characteristics length |
| D. | Mass no |
| Answer» D. Mass no | |
| 147. |
The boundary conditions in case of transient heat conduction in infinite thick solids are(i) t (x = 0) = t i(ii) t (0, T) = t a for T greater than zero(iii) t (infinity, T) = t i for T greater than zeroIdentify the correct statements |
| A. | 1 and 2 |
| B. | 1 and 3 |
| C. | 2 and 3 |
| D. | 1, 2 and 3 |
| Answer» E. | |
| 148. |
The temperature perturbation at all the surface has penetrated to the depth (Where, T is time constant and α is thermal diffusivity.) |
| A. | 1.6 (α T)^1/2 |
| B. | 2.6 (α T)^1/2 |
| C. | 3.6 (α T)^1/2 |
| D. | 4.6 (α T)^1/2 |
| Answer» D. 4.6 (α T)^1/2 | |
| 149. |
At the penetration depth d, there will be 1% perturbation at a time given by |
| A. | 4 d²/13 α |
| B. | 3 d²/13 α |
| C. | 2 d²/13 α |
| D. | d²/13 α |
| Answer» E. | |
| 150. |
What is the value of characteristics length for sphere? |
| A. | R/2 |
| B. | R/3 |
| C. | R/4 |
| D. | R/5 |
| Answer» C. R/4 | |