Basic Chemical Engineering Questions and Answers - Set 47 - ObjectiveBooks

Basic Chemical Engineering Questions and Answers - Set 47

Practice Test: Question Set - 47

1. A thin, flat & square plate measuring 2 m × 2 m is freely hanging in ambient air at 25°C. It is exposed to the solar radiation falling on one side of the plate at the rate of 500 W/m2. The plate temperature will remain constant at 30°C, if the convective heat transfer co-efficient is __________ W/m2 °C.
    (A) 50
    (B) 100
    (C) 150
    (D) 200

2. What is the critical radius of insulation (cms) for a metallic cylinder, if the convective heat transfer co-efficient with the ambient atmosphere is 5 W/m2. °K? Thermal conductivity of metal and insulation material are 40 and 0.1 W/m.°K respectively.
    (A) 2
    (B) 8
    (C) 10
    (D) 40

3. Pick out the correct statement
    (A) Jet engine can work, where there is no atmosphere
    (B) Rocket engines cannot work, where there is no atmosphere
    (C) Rocket engines carry oxygen required for the combustion in the form of oxidiser
    (D) Jet engines also carry oxidizer

4. For which pair of the fuel gases, calorific value (C.V.) of one fuel is almost double that of the other on volume basis (i.e., kcal/Nm3) while the C.V. is same on weight basis (i.e., kcal/kg)?
    (A) Propane and acetylene
    (B) Propane and LPG
    (C) Sewage gas and gobar gas
    (D) B.F gas and coke oven gas

5. Lead is poured into the joint between two- __________ pipes.
    (A) Mild steel
    (B) Concrete
    (C) Cast iron
    (D) Asbestos cement

6. The critical pressure at which the latent heat of vaporization of steam becomes zero is __________ Kg/cm2.
    (A) 273.15
    (B) 225.65
    (C) 100.03
    (D) 373.15

7. In a forced draft cooling tower, water is cooled from 95 to 80°F by exposure to air with a wet bulb temperature of 70°F. In this case, the
    (A) Range is 15°F
    (B) Approach is 10°F
    (C) Both (a) & (b)
    (D) Neither (a) nor (b)

8. The emf of a Deniell cell “Zn | Zn2+ || Cu2+ | Cu” can be increased by
    (A) Decreasing the surface area of the electrodes
    (B) Increasing the concentration of zinc sulphate solution
    (C) Increasing the surface area of the electrodes
    (D) Increasing the concentration of copper sulphate solution

9. The diffusion co-efficient of Ni in Cu at 1000 K is 1.93 × 10-16 m2S-1 and it is 1.94 × 10-14 m2S-1 at 1200 K. The activation energy (in k. J.mole-1) for the diffusion of Ni in Cu is
    (A) 130
    (B) 180
    (C) 230
    (D) 250

10. Which of the following materials does not form adherent oxide film on surface?
    (A) Copper
    (B) Nickel
    (C) Aluminium
    (D) Gold & silver

11. Electrostatic separation of minerals from each other is based on their differences in the following property.
    (A) Densities
    (B) Magnetic permeabilities
    (C) Electrical conductivities
    (D) Hardness

12. Steel produced from phosphatic iron is __________ in nature.
    (A) Malleable
    (B) Ductile
    (C) Brittle
    (D) Tough

13. While the recrystallisation temperature for pure metals is 0.3 Tm, the same for alloys is equal to __________ × Tm (where, Tm Melting temperature).
    (A) 0.25
    (B) 0.45
    (C) 0.70
    (D) 0.95

14. Though tin occurs lower than iron in the electrochemical series, yet it is coated on steel for corrosion protection, because of its
    (A) Lower cost
    (B) Abundant availability
    (C) Resistance to vegetable acids as the tin plate are commercially used in 'canning' industry
    (D) None of these

15. Which of the following properties of a solid is not dependent on crystal imperfection?
    (A) Ductility
    (B) Semi-conductivity
    (C) Melting point
    (D) Yield stress

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