Practice Pakistan's most useful MCQs for competitive exams

______________________ iron is produced by the annealing of white cast iron?

• (A)  Malleable
• (B)  Nodular
• (C)  Ductile
• (D)  Grey

Answer

Submitted By :Ali Uppal

With increase in impurities in metals, their corrosion resistances____________________?

• (A)  Increase
• (B)  Decrease
• (C)  Remain same
• (D)  May increase or decrease; depending on the type of metal

Answer

Submitted By :Ali Uppal

In the blast furnace, incorporation of water vapour in the blast gives the following effect ?

• (A)  Increases the reducing potential of the gas
• (B)  Increases the flame temperature
• (C)  No significant change occurs
• (D)  Increases the hydrogen content in the metal

Answer

Submitted By :Ali Uppal

The product out from a cupola is called ____________________?

• (A)  Wrought iron
• (B)  Pig iron
• (C)  Cast iron
• (D)  None of these

Answer

Submitted By :Ali Uppal

The transition temperature at which all the ferromagnetic materials become paramagnetic materials is termed as the ‘Curie temperature’. Its value for cobalt is ______________ °C?

• (A)  768
• (B)  1127
• (C)  1359
• (D)  1480

Answer

Submitted By :Ali Uppal

Super conduction in metals is observed at a temperature of ________________ °K?

• (A)  <100
• (B)  >100
• (C)  About 273
• (D)  About 373

Answer

Submitted By :Ali Uppal

Maximum amount of thermal radiation is emitted at all wavelengths at any specified temperature by a/an ______________ body?

• (A)  Grey
• (B)  Black
• (C)  Opaque
• (D)  White

Answer

Submitted By :Ali Uppal

Catalyst used in the catalytic converter employed in automobiles to convert CO into CO2 and for complete oxidation of un-burnt hydrocarbons is___________________?

• (A)  Nickel
• (B)  Cobalt
• (C)  Vanadium
• (D)  Platinum

Answer

Submitted By :Ali Uppal

Cascade control is___________________?

• (A)  The continuous adjustment of the set point index of an automatic control loop by a primary(master) controller
• (B)  Used when changes in process conditions cause serious upsets in the controlled variable
• (C)  Useful to control flow from temperature
• (D)  All A, B & C

Answer

Submitted By :Ali Uppal

For the irreversible reaction, Ca+ 2C = Ca C2 , Δ H°298 = – 60000 J . mole-1 . If a system initially containing 2 moles of calcium, 3 moles of carbon and 1 mole of calcium carbide is allowed to react to completion, the heat evolved at 298 K will be__________________?

• (A)  30,000 J
• (B)  60,000 J
• (C)  90,000 J
• (D)  2,40,000 J

Answer

Submitted By :Ali Uppal