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# NHPC JE’21 ME: Daily Practices Quiz. 01-Nov-2021

Quiz: Mechanical Engineering
Exam: NHPC JE
Topic: Material Science

Each question carries 1 mark
Negative marking: 1/4 mark
Time: 6 Minutes

Q1. Which one of the following is not intensive property of the system?
(a) Volume
(b) Pressure
(c) Temperature
(d) Density

Q2. Which of the following is an example of irreversible process?
(a) Polytropic expansion of fluid
(b) Unrestricted expansion of gases
(c) Isothermal expansion
(d) Electrolysis

Q3. A cup of 10 cm height and 5 cm diameter is to be made from a sheet metal of 2 mm thickness. The number of deductions necessary will be
(a) one
(b) two
(c) three
(d) four

Q4. The bending force required for U-bending, V – bending and Edge – bending will be in the ratio of
(a) 1: 2: 0.5
(b) 2: 1: 0.5
(c) 1: 2: 1
(d) 1: 1: 1

Q5. An oil of specific gravity 0.9 has viscosity of 0.28 stokes at 38°C. What will be its viscosity in Ns/m²?
(a) 0.2520
(b) 0.0311
(c) 0.0252
(d) 0.0206

Q6. What is the pressure difference between inside and outside of a soap bubble?
(a) 2σ/d
(b) 4σ/d
(c) 8σ/d
(d) 12σ/d
Where σ is surface tension and d is the diameter of the droplet.

Solutions

S1. Ans. (a)
Sol. The property which is not intensive means it is extensive.
So, volume is extensive property.
Extensive Property: The property which does depends on the amount of matter contain in the system

S2. Ans. (b)
Sol. Irreversible process: It is actual process and on P-V diagram or T-S diagram or on any thermodynamics diagram it is not represented by a continuous line.
So, Unrestricted expansion of gases is an irreversible process.

S3. Ans.(c)
Sol. D=√(d^2+4dh)=√(5^2+4×5×10)=15
Limiting draw ratio=D/d=15/5=3
The number of deductions necessary will be three.

S4. Ans. (b)
Sol. The bending force required for U-bending, V – bending and Edge – bending will be in the order of
U – bending > V – bending > Edge – bending

S5. Ans. (c)
Sol. Dynamic viscosity,
μ=ρυ=(0.9×1000)×(0.28×10^(-4) )
=0.0252 Ns/m²

S6. Ans. (c)
Sol. Pressure difference between inside and outside of a soap bubble = 8σ/d

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