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# UPPSC Lec’21 ME: Daily Practices Quiz. 04-Dec-2021

Quiz: Mechanical Engineering
Exam: UPPSC AE/Lecturer
Topic: Miscellaneous

Each question carries 3 mark
Negative marking: 1 mark
Time: 8 Minutes

Q1. Resilience of a bolt may be increased by
(a) increasing its length
(b) increasing its shank diameter
(c) increasing diameter of threaded portion

Q2. The stream function for a two-dimensional flow is given by ψ=xy. The velocity at (1, 2) is
(a) √5
(b) 5
(c) 2√5
(d) √2

Q3. The method of testing hardness by Brinell test is based on the principle of
(a) Indentation
(b) Fracture
(c) Scratching
(d) Rebound

Q4. In parson’s steam turbine, steam expands in
(a) nozzles only
(c) partly in nozzles and partly in blades
(d) none of the above

Q5. The spark plug gap is of the order in case of a petrol engine is
(a) 0.10 mm
(b) 0.60 mm
(c) 0.01 mm
(d) 0.15 mm

S6. What is the purpose of the use of Tetra ethyl lead in fuel?
(a) To increase the lubrications
(b) To decrease octane number
(c) To increase octane number
(d) None of the above

Solutions

S1. Ans. (a)
Sol. Resilience of a bolt may be increased by increasing its length.

S2. Ans. (a)
Sol. Given, Stream function ψ=xy
We know that
∂ψ/∂x= v and ∂ψ/∂y=-u
So, u=-∂ψ/∂y=-x=-1 (putting x=1)
v=∂ψ/∂x=y=2 (Putting y=2)
So, the velocity at (1, 2) is √(u^2+v^2 )=√(〖(-1)〗^2+〖(2)〗^2 )=√5

S3. Ans. (a)
Sol. In Brinell hardness number, the hardened steel ball is used as indenter.
Brinell hardness number =2P/πD(D-√(D^2-d^2 ))

S4. Ans. (c)
Sol. In parson’s steam turbine, steam expands partly in nozzles and partly in blades.

S5. Ans. (b)
Sol. The spark plug gap is of the order in case of a petrol engine is 0.6 mm.

S6. Ans. (c)
Sol. The purpose of the use of Tetra ethyl lead in fuel is to increase octane number

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