# Important 1000 MCQ For CIVIL Junior Engineer

21. The velocity of exit waste gases
should be a minimum of ____ of wind
speed to prevent down draught.

A. 0.5 B. 1.5
C. 2.5 D. 3.5

Ans. C

Solution.

• The velocity of exit, ve should be the min. of 2.5 of wind speed to prevent down draught. It can be see in rocket in which, Ve = me√yRTe Where y is specific heat ratio.

22. The device used for the easy
separation of dry dust of 10 to 100
µm size is ______.

A. cyclone
B. gravity settling chamber
C. bag filter
D. scrubber
Ans. A

Solution

• A cyclonic separation is a method of removing particulates from an air, gas or liquid stream, without the use of filters, through vortex separation. When removing particulate matter from liquids, a hydrocyclone is used; while from gas, a gas cyclone is used.

23. Consider the following factors

B) Large variations in stress
C) Large stress concentrations
Those associated with fatigue failure
would include ________.

A. A and B B. A and C
C. B and C D. A, B and C

Ans. D

Solution :

• In case of loading, the fatigue condition will occur when load is applied zero-to-max-to-zero & when varying load or stresses acting on member. In case of stress, the fatigue condition will occur when any tensile stress is acting on a member & then released suddenly.

24. In a truss girder of a bridge, a
diagonal consists of mild steel flat 400
ISF and carries a pull of 800 kN. If the
gross diameter of the rivets is 26mm,
then the number of rivets required in
the splice is ______.

A. 6 B. 7
C. 8 D. 9

Ans. D

Solution :

• Strength of the one rivet = 2.5kb.d.t.fu/ymo

Where, ymo is factor of safety

Kb is least of ( P/3d0)-.25, e/3d0, 10. Whichever is less.
Kb = 0.523 & for 400 ISF t = 8mm.

So, strength of one rivet = 2.5 × 0.523 × 26 × 8 × 400/1.25 = 87.027 kN

No of rivets = 800/87.027 = 9.1

25. The problem of lateral buckling can
arise only in those steel beams which
have ______.

A. moment of inertia about the
bending axis larger than the other
B. moment of inertia about the
bending axis smaller than the other
C. fully supported compression
flange
D. None of these

Ans. B

Solution:

• From the relation, P = ∏2EI/L2 So the buckling is depend on moment of inertia about the bending axis. Lateral buckling occur when the moment of inertia about the bending axis will be smaller than other.

Important 1000 MCQ For CIVIL Junior Engineer : Part 1

26.For unstiffened flange of a beam in
flexural compression, the maximum
allowable outstand is equal to
______.

A. 20 t B. 16 t
C. 32 t D. 14 t

Ans. B

Solution :

• for un-stiffed flange The max. allowable outstand = least of 16t or 200mm. whichever is less.

27. And angle section can be used as
purlin when slope of the roof truss is
_______.

A. Between 40° and 70°
B. Less than 30°
C. Greater than 30°
D. Less than 45°

Ans. B

Solution :

28. The buckling load in a steel column is
_______.

A. inversely proportional to square of
length
B. Directly proportional to the
slenderness ratio
C. Inversely proportional to the
slenderness ratio
D. Directly proportional to length

Ans. C

Solution:

• The buckling load, P = ∏2EI/L2 p is inversely proportional to the slenderness ratio

29. The effective length of battened
column is increased by _____.

A. 10% B. 7%
C. 12% D. 25%

Ans. A

Solution:

• The actual length L of the compression member should be taken as the length from centre-to-centre of intersection of supporting members or the cantilevered length in the case of free standing struts. & the effective length increased by 10% for battened columns.

30. Angle of inclination of the lacing bar
with the longitudinal axis of the
column should preferably be between
_______.

A. 10° to 30° B. 30° to 80°
C. 40° to 70°. D. 20° to 70°

Ans. C

Solution

• Lacing bar shall be inclined at 400 to 700 to axis of built up member or longitudinal axis of the member.

Important 1000 MCQ For CIVIL Junior Engineer : Part 2