This set of Strength of Materials Multiple Choice Questions on “Definition of Torque”.
1. Torque is __________ moment.
a) Twisting
b) Shear
c) Bending
d) Couple
Answer: a
Clarification: 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. Twisting moment is a product of __________ and the radius.
a) Direction
b) Velocity
c) Force
d) Acceleration
Answer: c
Clarification: 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. Torsion is denoted by __________
a) R
b) Q
c) T
d) N
Answer: c
Clarification: 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. The SI units for torsion is __________
a) N m
b) N
c) N/m
d) m
Answer: a
Clarification: 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. _____________ torsion is produced when twisting couple coincides with the axis of the shaft.
a) Exact
b) Pure
c) Nominal
d) Mild
Answer: b
Clarification: 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. Which of the following is known as Re-entrant mouthpiece?
a) External Mouthpiece
b) Convergent Mouthpiece
c) Internal Mouthpiece
d) Cylindrical Mouthpiece
Answer: c
Clarification: 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. Micrometre contraction gauge is used to determine ___________
a) Cv
b) Cc
c) Ca
d) Cd
Answer: b
Clarification: 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. What is the general value for coefficient of contraction?
a) 0.64
b) 0.67
c) 0.66
d) 0.7
Answer: a
Clarification: 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. The Cd value for internal mouthpiece running free is __________
a) 0.6
b) 0.5
c) 0.7
d) 0.8
Answer: b
Clarification: 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. _______ 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
d) Velocity of head
Answer: c
Clarification: 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. 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
Answer: a
Clarification: 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. For measuring low discharges _____________ notch is preferred.
a) Rectangular
b) Stepped
c) Trapezoidal
d) Triangular
Answer: d
Clarification: 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. Which of the following is also known as V notch?
a) Trapezoidal
b) Stepped
c) Triangular
d) Sharp edged
Answer: c
Clarification: 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. 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
Answer: b
Clarification: 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. _____ converts mechanical energy into hydraulic energy.
a) Dynamo
b) Pump
c) Turbine
d) Generator
Answer: b
Clarification: 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.