Practice Pakistan's most useful MCQs for competitive exams

High speed steel tools retain their hardness upto a temperature of _____________ °C?

• (A)  500
• (B)  750
• (C)  900
• (D)  1100

Answer

Submitted By :Ali Uppal

When iron is rusted, it is__________________?

• (A)  Converted to a fine powder
• (B)  Reduced
• (C)  Oxidised
• (D)  None of these

Answer

Submitted By :Ali Uppal

Caustic soda is transported in _____________ lined containers ?

• (A)  Glass
• (B)  Nickel
• (C)  Neoprene
• (D)  Either

Answer

Submitted By :Ali Uppal

_______________ is a donor impurity for semi-conductors ?

• (A)  Boron
• (B)  Antimony
• (C)  Gallium
• (D)  None of these

Answer

Submitted By :Ali Uppal

Non-ferrous metals and hard steels do not exhibit a definite yield point, when pulled in the testing machine and hence for these cases, a better measure of their elastic properties is defined by the ______________ stress?

• (A)  Ultimate
• (B)  Yield point
• (C)  Proof
• (D)  None of these

Answer

Submitted By :Ali Uppal

How many molecules per unit cell are there in a face centred cubic lattice ?

• (A)  2
• (B)  4
• (C)  6
• (D)  8

Answer

Submitted By :Ali Uppal

Which one occupies the lowermost position in the electromotive series of metals ?

• (A)  Aluminium
• (B)  Noble metals (Ag, Pt, Au)
• (C)  Zinc
• (D)  Alkali metals (K, Na, Li)

Answer

Submitted By :Ali Uppal

Lead pipes are not safe for carrying drinking water, because water, containing dissolved oxygen attacks lead thereby forming poisonous Pb(OH)2. Lead pipes are readily corroded by___________________?

• (A)  Dilute HCl
• (B)  Acetic acid
• (C)  Concentrated H2SO4
• (D)  None of these

Answer

Submitted By :Ali Uppal

Nickel as a material of construction__________________?

• (A)  Is used as an alloying element for both ferrous & non-ferrous alloys
• (B)  Is paramagnetic below 415° C (its Curie temperature)
• (C)  Diamagnetic
• (D)  Has a body centred cubic (bcc) crystal lattice structure

Answer

Submitted By :Ali Uppal

Tin base and lead base alloys are used for bearing materials. Tin compared to lead has lower_________________?

• (A)  Price
• (B)  Corrosion resistance
• (C)  Thermal conductivity
• (D)  Abundant availability

Answer

Submitted By :Ali Uppal