Practice Pakistan's most useful MCQs for competitive exams

The capacity of a centrifugal pump Can be increased by increasing the_________________?

• (A)  Impeller diameter or speed
• (B)  Number of pumps and joining them in series
• (C)  Number of pumps and joining them in parallel
• (D)  All

Answer

Submitted By :Ali Uppal

Curve III in the bellow diagram represents a/an________________?

• (A)  Dilatent fluid
• (B)  Pseudo plastic fluid
• (C)  Ideal plastic
• (D)  None of these

Answer

Submitted By :Ali Uppal

Umf is the minimum fluidisation velocity for a bed of particles. An increase in the superficial gas velocity from 2 Umf to 2.5 Umf results in (all velocities are smaller than the entrainment velocity of the particles) no change in the_______________?

• (A)  Drag on particles
• (B)  Drag on column walls
• (C)  Bed height
• (D)  Bed voidage

Answer

Submitted By :Ali Uppal

What is the unit of kinematic viscosity in SI unit ?

• (A)  M2/sec
• (B)  N/m2. sec
• (C)  Kg. sec/m
• (D)  None of these

Answer

Submitted By :Ali Uppal

A rectangular surface 3′ × 4′, has the lower 3 edge horizontal and 6′ below a free oil surface (sp. gr. 0.8). The surface inclination is 300 with the horizontal. The force on one side of the surface is (where, y = specific weight of water) ?

• (A)  39.6y
• (B)  48y
• (C)  49.2y
• (D)  58y

Answer

Submitted By :Ali Uppal

A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, the power consumed now will be _____________ hp?

• (A)  0.5
• (B)  2
• (C)  4
• (D)  1

Answer

Submitted By :Ali Uppal

Power number is the ratio of____________________?

• (A)  Drag stress to inertial stress
• (B)  Inertial stress to drag stress
• (C)  Inertial stress to gravitational stress
• (D)  Gravitational stress to drag stress

Answer

Submitted By :Ali Uppal

A hydraulic press has a ram of 10 cms in diameter and a plunger of 1 cm in diameter. The force required on the plunger to raise a weight of 10 tons on the ram is _____________ kg?

• (A)  10
• (B)  100
• (C)  1000
• (D)  10000

Answer

Submitted By :Ali Uppal

Mach number is defined as the ratio of the local flow velocity to the sonic velocity in the fluid. For what value of Mach number, the gases are considered incompressible ?

• (A)  < 0.3
• (B)  > 3
• (C)  50
• (D)  1

Answer

Submitted By :Ali Uppal

Propeller type centrifugal pumps are most suitable for__________________?

• (A)  High capacity at high heads
• (B)  High capacity at low heads
• (C)  Low capacity at high heads
• (D)  Low capacity at low heads

Answer

Submitted By :Ali Uppal