Engineering Questions with Answers - Multiple Choice Questions

# Strength of Materials MCQs Definition of Torque

1 - Question

Torque is __________ moment.
a) Twisting
b) Shear
c) Bending
d) Couple

Explanation: A cylindrical shaft is subjected to twisting moment or torque when a force is acting on the member tangentially at some radius in a plane of its cross section.

2 - Question

Twisting moment is a product of __________ and the radius.
a) Direction
b) Velocity
c) Force
d) Acceleration

Explanation: Twisting moment will be equal to the product of force and radius. When a shaft is subjected to a twisting moment, every cross section of the shaft will surely experience shear stress.

3 - Question

Torsion is denoted by __________
a) R
b) Q
c) T
d) N

Explanation: If the moment is applied in a plane perpendicular to the longitudinal axis of the beam (or) shaft it will be subjected to torsion. Torsion is represented or denoted by T.

4 - Question

The SI units for torsion is __________
a) N m
b) N
c) N/m
d) m

Explanation: As torsion is a product of perpendicular force and radius, the units will be N m.
Torque is also known as torsion or twisting moment or turning moment.

5 - Question

_____________ torsion is produced when twisting couple coincides with the axis of the shaft.
a) Exact
b) Pure
c) Nominal
d) Mild

Explanation: When a member is subjected to the equal and opposite twisting moment at its ends, then the member is said to be subjected under pure torsion. Pure Torsion is often produced when the axis of the twisting couple coincides with the axis of the shaft.

6 - Question

Which of the following is known as Re-entrant mouthpiece?
a) External Mouthpiece
b) Convergent Mouthpiece
c) Internal Mouthpiece
d) Cylindrical Mouthpiece

Explanation: According to the position, mouthpieces are classified as an external mouthpiece and internal mouthpiece. If the tube projects inside the tank, it is called an internal mouthpiece or re-entrant or borda’s mouthpiece.

7 - Question

Micrometre contraction gauge is used to determine ___________
a) Cv
b) Cc
c) Ca
d) Cd

Explanation: The coefficient of contraction may be determined experimentally by measuring the radius of jet as vena contact with the help of micro meter contraction gauge. This method is not accurate because it is very difficult to measure the correct radius of jet.

8 - Question

What is the general value for coefficient of contraction?
a) 0.64
b) 0.67
c) 0.66
d) 0.7

Explanation: The ratio of the area of a jet at vena contracta to the area of orifice is known as the coefficient of contraction. The value of Cc varies from 0.61 to 0.69 for different orifices. Generally, for sharp edged orifice the value of Cc may be taken as 0. 64.

9 - Question

The Cd value for internal mouthpiece running free is __________
a) 0.6
b) 0.5
c) 0.7
d) 0.8

Explanation: The Cd value for internal mouthpiece running free is 0.5.
Type Of Mouthpiece Value of Cd
External cylindrical mouthpiece 0.855
Internal mouthpiece running free 0.5
Internal mouthpiece running full 0.707

10 - Question

_______ is the velocity with which water reaches the notch or before it flows over it.
a) Velocity of contact
b) Velocity of moment
c) Velocity of approach

Explanation: The velocity of approach is defined as the velocity with which water reaches the notch or weir before it flows over it. This velocity of approach creates an additional head “ha” equal to Va2 / 2g and effect head over the notch is increased to H+ha.

11 - Question

Which of the following formula was proposed by Bazin?
a) m(2g)1/2×LH3/2
b) m(2g) 1/2×H3/2
c) n(2g) 1/2×LH4/3
d) n(2g)1/2×LH3/2

Explanation: Bazin proposed the following formula for the discharge over rectangular weir:
Q = m(2g) 1/2× L H3/2.
Where m = 0.405 + 0.003/H.

12 - Question

For measuring low discharges _____________ notch is preferred.
a) Rectangular
b) Stepped
c) Trapezoidal
d) Triangular

Explanation: A triangular notch is preferred to a rectangular notch due to
i. The nappe emerging from a triangular notch has the same shape for all heads. As such the value for the triangular notch is constant for all heads.
ii. The expression for discharge for right angle triangle law not is very simple.

13 - Question

Which of the following is also known as V notch?
a) Trapezoidal
b) Stepped
c) Triangular
d) Sharp edged

Explanation: A triangular notch also called a v notch is of triangle shape with apex down. The expression of the discharge over triangular notch or weir is Q = 8/15 Cd (2g) 1/2 × H 5/2.

14 - Question

Calculate the discharge over rectangular Weir of 3 metres length under the head of 400mm.Use Francis formula.
a) 1.268 m3/s
b) 1.396 m3/s
c) 1.475 m3/s
d) 1.528 m3/s

Explanation: Francis formula for discharge Q = 1.84 LH3/2.
Given L = 3m & H = 0.4m
Q = 1.84 × 3 × (0.4)3/2.
Q = 1.396 m3/s.

15 - Question

_____ converts mechanical energy into hydraulic energy.
a) Dynamo
b) Pump
c) Turbine
d) Generator

Explanation: A pump is a mechanical device which converts the mechanical energy into hydraulic energy. The hydraulic energy is in the form of pressure energy. The pumps are generally used for lifting liquid from a lower level to a higher level.

16 - Question

### Strength of Materials MCQs Torsion Equation

Torsional sectional modulus is also known as _________
a) Polar modulus
b) Sectional modulus
c) Torsion modulus
d) Torsional rigidity

Explanation: The ratio of polar moment of inertia to radius of section is called Polar modulus or Torsional section modulus. Its units are mm3 or m3 (in SI).

17 - Question

________ is a measure of the strength of shaft in rotation.
a) Torsional modulus
b) Sectional modulus
c) Polar modulus
d) Torsional rigidity

Explanation: The polar modulus is a measure of the strength of shaft in rotation. As the value of Polar modulus increases torsional strength increases.

18 - Question

What are the units of torsional rigidity?
a) Nmm2
b) N/mm
c) N-mm
d) N

Explanation: The product of modulus of rigidity (C) and polar moment of inertia (J) is called torsional rigidity. Torsional rigidity is a torque that produces a twist of one radian in a shaft of unit length.

19 - Question

The angle of twist can be written as ________
a) TL/J
b) CJ/TL
c) TL/CJ
d) T/J

Explanation: The angle of Twist = TL/CJ
Where T = Torque in Nm
L = Length of shaft
CJ = Torsional rigidity.

20 - Question

The power transmitted by shaft SI system is given by __________
a) 2πNT/60
b) 3πNT/60
c) 2πNT/45
d) NT/60 W

Explanation: In SI system, Power (P) is measured in watts (W) ; P = 2πNT/60
Where T = Average Torque in N.m
N = rpm
= 2πNT/ 45 1 watt = 1 Joule/sec = 1N.m/s.

21 - Question

Area of catchment is measured in ___________
a) mm3
b) Km2
c) Km
d) mm

Explanation: Catchment area can be defined as the area which contributes the surplus water present over it to the stream or river. It is an area which is responsible for maintaining flow in natural water bodies. It is expressed in square kilometres.

22 - Question

______ catchment area is a sum of free catchment area and intercepted catchment area.
a) Total
c) Combined
d) Overall

Explanation: Combined catchment area is defined as the total catchment area which contributes the water in to stream or a tank. Combined Catchment area = Free catchment area + intercepted catchment area.

23 - Question

___________ has steep slopes and gives more run off.
a) Intercepted Catchment Area
b) Good Catchment Area
c) Combined Catchment Area
d) Average Catchment Area

Explanation: Good catchment area consists of hills or rocky lands with steep slopes and little vegetation. It gives more run off.

24 - Question

How many number of rain gauge stations should be installed an area between 250 to 500 km2.
a) 2
b) 4
c) 3
d) 5

Explanation: 3 number of rain gauge stations should be installed an area between 250 to 500 km2.
Area of Basin(Km2) Number of Rain gauge stations
< 125 1
125 – 250 2
250 – 500 3

25 - Question

Trend of rainfall can be studied from _______
a) Rainfall graphs
b) Rainfall records
c) Rainfall curves
d) Rainfall cumulatives

Explanation: Rainfall records are useful for calculating run off over a basin. By using rainfall records estimate of design parameters of irrigation structures can be made. The maximum flow due to any storm can be calculated and predicted.

26 - Question

Estimation of run off “R” is 0.85P-30.48.
The above formula was coined by _____
a) Lacey
b) Darcy
c) Khosla
d) Ingli

Explanation: Run off can be estimated by
R= 0.85P-30.48
Where R = annual runoff in mm
P = annual rainfall in mm.

27 - Question

Monsoon duration factor is denoted by ________
a) P
b) S
c) F
d) T

Explanation: Monsoon duration factor is denoted by F.
Class of Monsoon Monsoon Duration Factor (F)
Very Short 0.5
Standard length 1.0
Very long 1.5

28 - Question

Runoff coefficient is denoted by _______
a) P
b) N
c) K
d) H

Explanation: The runoff coefficient can be defined as the ratio of runoff to rainfall. Rainfall and runoff can be interrelated by runoff coefficient.
R = KP
K = R/P [K = is a runoff Coefficient depending on the surface of the catchment area].

29 - Question

_________ is a graph showing variations of discharge with time.
a) Rising limb graph
b) Crest graph
c) Hydraulic graph
d) Gauge graph

Explanation: Hydrograph is a graph showing variations of discharge with time at a particular point of the stream. The hydrograph shows the time distribution of total run off at a point of measurement. Maximum flood discharge can also be calculated by using hydrograph.

30 - Question

Calculate the torque which a shaft of 300 mm diameter can safely transmit, if the shear stress is 48 N / mm2.
a) 356 kNm
b) 254 kNm
c) 332 kNm
d) 564 kNm

Explanation: Given, the diameter of shaft D = 300 mm
Maximum shear stress fs = 48 N/mm2.
Torque = T = π/16 fs D3
= 254469004.9 Nmm
= 254 kNm.

31 - Question

### Strength of Materials MCQs Shear Stress and Twisting Moment

The intensity of shear stress at a section is ______ to the distance of the section from the axis of the shaft.
a) Inversely proportional
b) Directly proportional
c) Equal
d) Parallel

Explanation: The intensity of shear stress at a section is directly proportional to the distance of the section from axis of the shaft. The shear stress at a distance from the centre of the shaft is given by fs/R × r.

32 - Question

The shear stress is ____________ at the axis of the shaft.
a) Minimum
b) Maximum
c) Zero
d) Uniform

Explanation: The shear stress is zero at the axis of the shaft and the shear stress is linearly increasing to the maximum value at the surface of the shaft.

33 - Question

The shear stress at the outer surface of hollow circular section is _________
a) Zero
b) Maximum
c) Minimum
d) Can’t determined

Explanation: The shear stress in a hollow circular section varies from maximum at the outer surface to a minimum (but not zero) in the inner face. The minimum value should be greater than zero.

34 - Question

The hollow shaft will transmit greater _______ then the solid shaft of the same weight.
a) Bending moment
b) Shear stress
c) Torque
d) Sectional Modulus

Explanation: For the same maximum shear stress, the average shear stress in a hollow shaft is greater than that in a solid shaft of the same area. Hence the hollow shaft will transmit greater torque than the solid shaft of the same weight.

35 - Question

The process of measurement of discharge and water level of a river is called _________
a) Meandering
b) River coursing
c) River gauging
d) Scouring

Explanation: The process of measurement of discharge and water level of a river is known as river gauge. It helps in determining the characteristics of flow different times during the year.

36 - Question

The quantity of losses in the river can be measured with an aid of ________
a) Runoff coefficient
b) Hydrograph
c) River Coursing
d) River gauging

Explanation: By measuring river discharge for number of years, it is possible to know the available and dependable supply. The river gauging helps in measuring discharge in the river and the quantity of losses can also be known.

37 - Question

The site for the river gauging station should not be liable to ____________
a) Silting
b) Coursing
c) Meandering
d) Runoff

Explanation: River gauging station site should be selected in such a way that the site should be stable and there should not be any choice of scouring and silting. At the gauge site, the river section should be at right angles to the flow of the river.

38 - Question

Stage discharge relationship method is also known as ________ method.
a) Velocity Volume
b) Velocity Area
c) Distance Area
d) Displacement Momentum

Explanation: Stage discharge relationship method is a direct method of computing a discharge in a stream by measuring velocity and area of flow. The place where such measurements are taken is known as velocity area station and the method is known as the velocity area method.

39 - Question

Velocity in a river flow can be calculated by using _________
a) By current meter
b) By emperical formulae
c) By infiltration method
d) By hydrograph

Explanation: The velocity flow at any point in an open channel or in a river can be most accurately and conveniently determined by a mechanical device called current metre in this device the velocity of flow can be read from rating table.

40 - Question

Which of the following method is not used in measuring the velocity of a stream?
a) By floats
b) By rod float
c) By hydrograph
d) By colour

Explanation: Hydrograph is a method of estimation of runoff. While the rest of the methods used in measuring the velocity of a stream/ river or canal. Hydrograph is a graph which shows the variations of discharge with respect to time.

41 - Question

The maximum flood discharge is also known as ___________
a) Peak flow
b) Maximum flow
c) Peak discharge
d) Peak flood

Explanation: The maximum rate of discharge during a period of runoff, which is caused by a storm, is called a peak flow maximum flood discharge. Estimation of maximum flood discharge is a first step in planning for flood regulation.

42 - Question

Which of the following method is used to estimate maximum flood discharge?
a) By travelling screen
b) By current meter
c) By physical indication of past floods
d) By salt velocity

Explanation: The results obtained by the physical indication of past floods methods are somewhat reliable. By oral enquiry in the villages situated on the banks of the river, the maximum water level attained in the past 35 years can be obtained. But this method is out-dated.

43 - Question

________formula is used only in southern India for calculating maximum flood discharge.
a) Dickens
b) Ryve’s
c) Lacey’s
d) Francis

Explanation: Ryve’s (1884) formula is used only in Southern India.
Q = C(A)2/3.
The coefficient “C” depends on the maximum intensity of rainfall and other factors such as shape slopes exedra of the catchment.

44 - Question

A catchment area of 30.5 km2 is situated in Central India calculate the maximum discharge coming from the catchment area.
a) 253.08 cumecs
b) 341.06 cumecs
c) 457.88 cumecs
d) 485.66 cumecs

Explanation: As the catchment area is situated in central India. Dicken’s formula is suitable and a maximum value of Dickens Coefficient is taken as 19.5
Q = CA3/4
Q = 19.5 × (30.5)3/4
Q = 253.08 cumecs.

45 - Question

If the catchment area is situated in north India, then what is the flood coefficient?
a) 10.45
b) 11.37
c) 12.6
d) 19.4