Practice Pakistan's most useful MCQs for competitive exams

The shear stress distribution for a fluid flowing in between the parallel plates, both at rest, is_______________?

• (A)  constant over the cross section
• (B)  parabolic distribution across the section
• (C)  zero at the mid plane and varies linearly with distance from mid plane
• (D)  zero at plates and increases linearly to midpoint

Answer

Submitted By :Ali Uppal

The boundary layer thickness at a distance of l m from the leading edge of a flat plate, kept at zero angle of incidence to the flow direction, is O.l cm. The velocity outside the boundary layer is 25 ml sec. The boundary layer thickness at a distance of 4 m is__________________?

• (A)  0.40 cm
• (B)  0.20 cm
• (C)  0.10 cm
• (D)  0.05 cm

Answer

Submitted By :Ali Uppal

Two pipes of same length and diameters d and 2d respectively are connected in series. The diameter of an equivalent pipe of same length is________________?

• (A)  less than d
• (B)  between d and 1.5 d
• (C)  between 1.5 d and 2d
• (D)  greater than 2d

Answer

Submitted By :Ali Uppal

The length of a pipe is 1 km and its diameter is 20 cm. If the diameter of an equivalent pipe is 40 cm, then its length is_____________________?

• (A)  32 km
• (B)  20 km
• (C)  8 km
• (D)  4 km

Answer

Submitted By :Ali Uppal

When time of closure tc = L/v0 (where L is length of pipe and v0 is speed of pressure wavE., the portion of pipe length subjected to maximum head is__________________?

• (A)  L/4
• (B)  L/3
• (C)  L/2
• (D)  L

Answer

Submitted By :Ali Uppal

A valve is suddenly closed in a water main in wl.ich the velocity is 1 m/sec and velocity of pressure wave is 981 m/ sec. The inertia head at the valve will be________________?

• (A)  1 m
• (B)  10m
• (C)  100m
• (D)  none of the above

Answer

Submitted By :Ali Uppal

In series-pipe problems_______________?

• (A)  the head loss is same through each pipe
• (B)  the discharge is same through each pipe
• (C)  a trial solution is not necessary
• (D)  the discharge through each pipe is added to obtain total discharge

Answer

Submitted By :Ali Uppal

If a sphere of diameter 1 cm falls in castor oil of kinematic viscosity 10 stokes, with a terminal velocity of 1.5 cm/sec, the coefficient of drag on the sphere is________________?

• (A)  less than 1
• (B)  between 1 and 100
• (C)  160
• (D)  200

Answer

Submitted By :Ali Uppal

The hydraulic grade line is_________________?

• (A)  always above the centre line of pipe
• (B)  never above the energy grade line
• (C)  always sloping downward in the direction of flow
• (D)  all of the above

Answer

Submitted By :Ali Uppal

The wake_______________?

• (A)  always occurs before a separation point
• (B)  always occurs after a separation point
• (C)  is a region of high pressure intensity
• (D)  none of the above

Answer

Submitted By :Ali Uppal