Chemical Engineering Basics MCQs

Question 1

Yield strength of a polycrystalline metal with an average grain size d, is proportional to

Accepted Answer

$${{	ext{d}}^{ - \frac{1}{2}}}$$

Answer

$${{	ext{d}}^{\frac{1}{2}}}$$

Answer

d

Answer

d-1

Question 2

Presence of sulphur in the fuel fired in a furnace

Accepted Answer

All of the above

Answer

Contributes to its heating value

Answer

Helps in electrostatic precipitation of ash from flue gases

Answer

Corrodes ducts & air preheater, if the flue gas temperature is low

Question 3

__________ furnace is generally used in the non-ferrous foundaries.

Accepted Answer

Indirect arc

Answer

Direct arc

Answer

Resistance

Answer

Induction

Question 4

Which of the following metals occurs in nature in their free metallic state?

Accepted Answer

None of these

Answer

Au & Ag

Answer

Pb & Zn

Answer

Cu & Ni

Question 5

Steels with high carbon equivalent have poor weldability, because in these steels during welding

Accepted Answer

Martensite forms in the heat affected zone leading to poor toughness/ductility of the weld

Answer

Carbon and other alloying elements get oxidised from the weld pool

Answer

Excessive ferrite forms in the heat affected zone leading to poor toughness of the weld

Answer

Segregation of carbon and other element occurs in the weld pool leading to poor properties of the weld

Question 6

In a counter flow heat exchanger, hot fluid enters at 170°C & leaves at 150°C, while the cold fluid enters at 50°C & leaves at 70°C. The arithmetic mean temperature difference in this case is __________ °C.

Accepted Answer

∞

Answer

20

Answer

60

Answer

120

Question 7

Dislocation cross-slip is difficult in those materials, which have

Accepted Answer

Low stacking fault energy

Answer

Large number of slip systems

Answer

High work hardening rate

Answer

Coarse grain size

Question 8

The most economical channel section for the fluid flow is the one for which the discharge is maximum for a given cross-sectional area. Vertical velocity distribution in an open channel for laminar flow can be assumed to be

Accepted Answer

Parabolic

Answer

Hyperbolic

Answer

Straight line

Answer

None of these

Question 9

__________ the exhaust gas is an indication of the incomplete combustion of fuel.

Accepted Answer

High % of CO in

Answer

Low temperature of

Answer

High temperature of

Answer

High % of CO2 in