250+ TOP MCQs on Mechanical Energy Balance and Answers

Basic Chemical Engineering Multiple Choice Questions & Answers (MCQs) on “Mechanical Energy Balance”.

1. Mechanical energy satisfy which of the following?
a) Completely Convertible
b) Non-convertible
c) Partially convertible
d) None of the mentioned

Answer: a
Clarification: Mechanical energy is completely convertible by an ideal engine.

2. Which of the following is not an example of mechanical energy?
a) Kinetic energy
b) Potential energy
c) Internal energy
d) Work

Answer: c
Clarification: Internal energy is not a mechanical energy.

3. Which of the following allows complete conversion of mechanical energy?
a) Frictionless process
b) Dissipative process
c) Mixing of components
d) All of the mentioned

Answer: a
Clarification: A frictionless process is reversible so it allows complete conversion of mechanical energy.

4. Which process allows complete conversion of mechanical energy?
a) Irreversible
b) Reversible
c) Reversible & Irreversible
d) None of the mentioned

Answer: b
Clarification: Reversible process so it allows complete conversion of mechanical energy.

5. The mechanical energy balance is the product of the equation of motion and which of the following?
a) Mass
b) Velocity
c) Volume
d) None of the mentioned

Answer: b
Clarification: The mechanical energy balance is the product of the equation of motion and velocity.

6. Bernoulli equation is valid for which process?
a) Reversible
b) Irreversible
c) Reversible & Irreversible
d) None of the mentioned

Answer: a
Clarification: Bernoulli equation is valid for the process in which loss of mechanical energy is zero, which is reversible.

7. What is the height difference of the water (density = 1000 Kg/m³), if the change in velocity is 2 m/s and change in pressure is 100 Pa?
a) 0.21 m
b) 0.42 m
c) 0.56 m
d) 0.84 m

Answer: a
Clarification: ∆h = (100/1000 + 2²/2)/10 = 0.21 m.

8. What is the height difference of the water (density = 1000 Kg/m³), if the change in velocity is 10 m/s and change in pressure is 500 Pa?
a) 1.01 m
b) 5.05 m
c) 10.1 m
d) 20.2 m

Answer: b
Clarification: ∆h = (500/1000 + 102/2)/10 = 5.05 m.

9. What is the height difference of the water (density = 1000 Kg/m3), if the change in velocity is 10 m/s and change in pressure is 1000 Pa?
a) 1.4 m
b) 2.9 m
c) 4.2 m
d) 5.1 m

Answer: d
Clarification: ∆h = (1000/1000 + 10²/2)/10 = 5.05 m.

10. What is the height difference of the water (density = 1000 Kg/m³), if the change in velocity is 6 m/s and change in pressure is 2000 Pa?
a) 1.2
b) 2.0
c) 3.6
d) 4.4

Answer: b
Clarification: ∆h = (2000/1000 + 6²/2)/10 = 2.0 m.

11. What is the reversible work done if 5 m³ of an ideal gas is compressed isothermally from 1 Pa to 5 Pa?
a) 4.41 J
b) 8.01 J
c) 10.20 J
d) 14.18 J

Answer: b
Clarification: V₂ = 1*5/5 = 1 m³, => W = –₅∫¹pdv = –₅∫¹ (5/v) dv = 5 ln5 = 8.04 J.

12. What is the reversible work done if 4 m³ of an ideal gas is compressed isothermally from 2 Pa to 8 Pa?
a) 2.01 J
b) 6.11 J
c) 8.56 J
d) 11.09 J

Answer: d
Clarification: V₂ = 2*4/8 = 1 m³, => W = –₄∫¹pdv = –₄∫¹ (8/v) dv = 8 ln4 = 11.09 J.

13. What is the reversible work done if 8 m³ of an ideal gas is compressed isothermally from 4 Pa to 16 Pa?
a) 12.48 J
b) 28.55 J
c) 44.36 J
d) 56.96 J

Answer: c
Clarification: V₂ = 8*4/16 = 2 m³, => W = –₈∫²pdv = –₈∫² (32/v) dv = 32 ln4 = 44.36 J.

14. What is the reversible work done if 4 m³ of an ideal gas is compressed adiabatically pV1.5 = K from 2 Pa to 16 Pa?
a) 4 J
b) 16 J
c) 24 J
d) 56 J

Answer: b
Clarification: V₂ = (2*4^1.5/16)^1/1.5 = 1 m³, => W = –₄∫¹pdv = –₄∫¹ (16/v^1.5) dv = 16 J.

15. What is the reversible work done if 4 m³ of an ideal gas is compressed adiabatically pV2.5 = K from 1 Pa to 32 Pa?
a) 18.6 J
b) 20.4 J
c) 24.6 J
d) 26.2 J

Answer: a
Clarification: V₂ = (1*4^2.5/32)^1/2.5 = 1 m³, => W = –₄∫¹pdv = –₄∫¹ (32/v^2.5) dv = 18.6 J.