MULTIPLE CHOICE QUESTIONS OF THERMODYNAMICS

1. A definite area or space where some thermodynamic process takes place is known as
(a) thermodynamic system 
(b) thermodynamic cycle
(c) thermodynamic process 
(d) thermodynamic law.


2. An open system is one in which
(a) heat and work cross the boundary of the system, but the mass of the working substance does not
(b) mass of working substance crosses the boundary of the system but the heat and work do not
(c) both the heat and work as well as mass of the working substances cross the boundary of the system
(d) neither the heat and work nor the mass of the working substances cross the boundary of the system.


3. An isolated system
(a) is a specified region where transfer of energy and/or mass take place
(b) is a region of constant mass and only energy is allowed to cross the boundaries
(c) cannot transfer either energy or mass to or from the surroundings
(d) is one in which mass within the system is not necessarily constant
(e) none of the above.


4. In an extensive property of a thermodynamic system
(a) extensive heat is transferred 
(b) extensive work is done
(c) extensive energy is utilised
(d) all of the above
(e) none of the above.


5. Which of the following is an intensive property of a thermodynamic system ?
(a) Volume 
(b) Temperature
(c) Mass 
(d) Energy.


6. Which of the following is the extensive property of a thermodynamic system ?
(a) Pressure 
(b) Volume
(c) Temperature
(d) Density.


7. When two bodies are in thermal equilibrium with a third body they are also in thermal equilibrium with
each other. This statement is called
(a) Zeroth law of thermodyamics 
(b) First law of thermodynamics
(c) Second law of thermodynamics 
(d) Kelvin Planck’s law.


8. The temperature at which the volume of a gas becomes zero is called
(a) absolute scale of temperature 
(b) absolute zero temperature
(c) absolute temperature
(d) none of the above.


9. The amount of heat required to raise the temperature of 1 kg of water through 1°C is called
(a) specific heat at constant volume 
(b) specific heat at constant pressure
(c) kilo calorie 
(d) none of the above.
.
10. The absolute zero pressure will be
(a) when molecular momentum of the system becomes zero
(b) at sea level 
(c) at the temperature of – 273 K
(d) under vacuum conditions 
(e) at the centre of the earth.


11. Absolute zero temperature is taken as
(a) – 273°C 
(b) 273°C
(c) 237°C 
(d) – 373°C.


12. Which of the following is correct ?
(a) Absolute pressure = gauge pressure + atmospheric pressure
(b) Gauge pressure = absolute pressure + atmospheric pressure
(c) Atmospheric pressure = absolute pressure + gauge pressure
(d) Absolute pressure = gauge pressure – atmospheric pressure.


13. The unit of energy in SI units is
(a) Joule (J) 
(b) Joule metre (Jm)
(c) Watt (W) 
(d) Joule/metre (J/m).


14. One watt is equal to
(a) 1 Nm/s 
(b) 1 N/min
(c) 10 N/s 
(d) 100 Nm/s
(e) 100 Nm/m.

15. One joule (J) is equal to
(a)1 Nm (b) kNm
(d) 10 Nm/s (d) 10 kNm/s.


ANSWERS :-

1. (a) 2. (c) 3. (c) 4. (e) 5. (b) 6. (b) 7. (a)
8. (b) 9. (c) 10. (a) 11. (a) 12. (a) 13. (a) 14. (a)
15. (a)

DIFFERENCE BETWEEN COLD WORKING AND HOT WORKING NICELY EXPLAINED !!

The metal working processes are derived into hot working and cold working processes. The division is on the basis of the amount of heating applied to the metal before applying  the mechanical force.Re-crystallization temperature is defined as the approximate minimum temperature at which complete re-crystallization of a cold work metal occurs with in a specified time.

In other words,The lowest level of heat at which the distorted grain structure of a metal is replaced by a strain-free grain structure.

HOT WORKING PROCESS:-

• Hot working is carried out above the recrystallization temperature and below the melting point. Hence the deformation of metal and recovery take place simultaneously.
• No internal or residual stresses are set-up in the metal in hot working process.
• If cracks and blow boles are present in the metal, they can be finished through hot working.
• Close tolerance can not be maintained.
• Surface finish of hot working process is comparatively not good.
• It results in improvements of properties like impact strength and elongation.
• Due to recrystallisation very negligible hardening of metal takes place.

COLD WORKING PROCESS:-

• Cold working is carried out below the recrystallization temperature. As such, there is no appreciable recovery.
• In cold working process internal or residual stresses are set-up in the metal.
• In cold working the existing cracks propagate and new cracks may develop.
• Better tolerance can be easily maintained.
• Surface finish of cold working process is better.
• It also results in improvements of properties like impact strength and elongation.
• It improves ultimate tensile strength, hardness, yield strength but reduces the corrosion resistance of strength of the metal.
• The stress required to cause deformation is much higher.

YOU MIGHT HAVE SEEN THESE LIGHTS IN CAR!! CHECK OUT THEIR FUNCTION

We all know that headlights must be turned on at night – after all, you can’t exactly be a safe driver if you can’t see anything.

However, you may have come across some laws or signs that may have confused you. For example, in certain mountain roads in California, you might see signs that indicate “D.

Additionally, you may have even seen the newest automobiles equipped with Daytime Running Lights – or DRLs for short. What’s the deal here?

Daytime running LEDs in cars were not initially added as a move to improve aesthetics or appeal. It was introduced for improving safety.Obviously, it is not applicable to most countries like India where all parts of inhabited land gets sun shine for a decent share of the day. LEDs were made standard for some European countries which do not receive sun light for most of 24 hours and in locations where bad weather is common weather. Now, a strip of LEDs either on the bumper or within the headlamp cluster is not going to look pretty. But the government wants you to have it. So, a win-win situation is created.Having your headlights on during these periods can make it infinitely easier to spot oncoming traffic and any other cars around you.

Even in the day, a car with headlights on is easier to spot than one with no headlights. It’s another precautionary measure on some newer vehicles to reduce the risks of collision.

Most studies done around the world have concluded that daytime running lights can decrease collisions by anywhere from 5 to 10 percent. This data is convincing enough that, in many countries, all automobiles sold are legally required to have DRLs installed. Canada, Norway, and Sweden are some of the many countries who abide by this law.

TECHNICAL ROUND QUESTIONS OF MARUTI SUZUKI INDIA LIMITED

Maruti Suzuki India Limited Mechanical Engg Questions and Answers

1. The purpose of jigs and fixtures are to

a. Increased production rate
b. Increased machining accuracy
c. Facilitate interchangeable manufacturing
d. Enable employ less skilled operators
e. All of the above

Ans:e

2. Tool life of the cutting tool is most affected by

a. Cutting speed
b. Tool geometry
c. Cutting feed and depth
d. Microstructure of material being cut
e. Not using coolant and lubricant
Ans:a

3. A feeler gauge is used to check

a. Radius
b. Screw pitch
c. Surface roughness
d. Unsymmetrical shape
e. Thickness of clearance
Ans:e

4. Metal in machining operation is removed by

a. Tearing chips
b. Distortion of metal
c. Shearing the metal across a zone
d. Cutting the metal across a zone
e. Pushing the metal with tool
Ans:c

5. Ductility of material can be defined as

a. Ability to undergo large permanent deformation in compression
b. Ability to recover its original form
c. Ability to undergo large permanent deformation in tension
d. All of the above
e. None of the above
Ans:a

6. Inconel is an alloy of

a. Nickel, chromium and iron
b. Nickel and copper
c. Nickel and chromium
d. Nickel and zinc
e. Nickel and lead

Ans:a

7. Casting defects caused by the molten metal is

a) Blow holes
b) Swell
c) Scab
d) All of the above
Ans.: d

8. Forming operation which does not involve rotation of work piece is

a) Spinning
b) Thread rolling
c) Ring rolling
d) Upsetting
Ans.: d

9. Greater forging capacity is achieved with

a) Mechanical press
b) Power hammer
c) Hydraulic press
d) None of them
Ans.: c

10. Which of the following welding process uses consumable electrodes

a) TIG
b) MIG
c) Thermit
d) Laser
Ans.: b

11. The crystal structure of alpha iron

a) BCC
b) FCC
c) HCP
d) Cubic
Ans.: a

12. Severe quenching can cause

a) Blow holes
b) Warping
c) Inclusions
d) Non of them
Ans.: b

13. Glass bead peening on components done to

a) Improve creep strength

b) Improve fatigue strength

c) Improve finish

d) Impart further coating

Ans.: b

14. Trajectory of a robot mean :

a) Path traced by the end effectors

b) Kinematics of Robot

c) Robot joints

d) Robot programming
Ans: a

15. Rayleigh’s method of computing the fundamental natural frequency is based on

a)Conservation of energy

b)Conservation of momentum

c)Conservation of masses

d)Laws of statics

Ans: a

Source-https://www.freshersworld.com/

YOU MIGHT HAVE SEEN VARIOUS EMPLOYEES OF A FACTORY WEARING A HARD HAT OF DIFFERENT COLOR!!LET'S UNDERSTAND THE MEANING OF THIS COLOR CODE!

You might have seen various employees of a factory wearing a hard hat of different color!!Let's understand the meaning of this color code!

Hard hats are made from hardened plastic and, as such, they have an expiry date because plastic deteriorates over time.  This means that they will need to be replaced periodically so it’s important that you check the expiry date on any hard hat that you use.  A hard hat’s service life starts when it is first used and that date should be recorded on the hat in indelible pen.  The maximum time for replacing a hard hat is five years, but it should be checked regularly for signs of wear or damage.  The hard hat suspension should be replaced on an annual basis – they’re widely available from work gear outlets.

Hard hats come in a range of colours, all of which are significant as it allows workers on site to identify who is who and what type of work they are undertaking.

DIFFERENCE BETWEEN PATH FUNCTION AND POINT FUNCTION NICELY EXPLAINED

Point Function

A point function is single valued function which always possesses a single - value is all states. For instance each of the thermodynamics properties has single - value in equilibrium and other states. These properties are called as point function or state function.In other words,we can say that point function are those function which depend upon the initial and final point of the curve and is not affected by the path of the curve ,even if the path of the function is changed but the initial and the final points are the same then the function will give the same value .Such as pressure, volume, enthalpy, internal energy.

Path Function

Those properties, which cannot be located on graph by a point but are given by area or show on the graph.In other words,path function are those functions whose value depends upon the path traced by them .If their path is changed keeping the initial and final point same , their value will change.For example work, heat, heat transfer.

IMPORTANT TERMS OF FLUID MECHANICS

Density (mass density): The mass per unit volume is defined as density. The unit used is kg/m³.The measurement is simple in the case of solids and liquids. In the case of gases and vapoursit is rather involved. The symbol used is ρ. Thecharacteristic equation for gases provides ameans to estimate the density from the measurement of pressure, temperature and volume.

Specific Volume: The volume occupied by unit mass is called the specific volume of the material. The symbol used is v, the unit being m³/kg. Specific volume is the reciprocal of density.In the case of solids and liquids, the change in density or specific volume with changesin pressure and temperature is rather small, whereas in the case of gases and vapours, densitywill change significantly due to changes in pressure and/or temperature.

Weight Density or Specific Weight: The force due to gravity on the mass in unit volume is defined as Weight Density or Specific Weight. The unit used is N/m³ .

Specific Gravity or Relative Density:  The ratio of the density of the fluid to thedensity of water—usually 1000 kg/m³ at a standard condition—is defined as Specific Gravityor Relative Density δ of fluids. This is a ratio and hence no dimension or unit is involved.

Compressible fluid -If the density of a fluid varies significantly due to moderate changes in pressure ortemperature, then the fluid is called compressible fluid.

Incompressible fluid-If the change in density of a fluid is small due to changes in temperature and or pressure, then the fluid is called incompressible fluid.

Buoyant force- If an object is immersed in or floated on the surface of fluid under static conditions a force acts on it due to the fluid pressure. This force is called buoyant force.


Archimedes principle -Archimedes principle can be stated as (i) a body immersed in a fluid is buoyed upby a force equal to the weight of the fluid displaced and (ii) a floating body displaces its own weight of the liquid in which it floats.

Reynolds number -Reynolds number is the ratio of inertia force to viscous force. As inertia force increases Reynolds number increases and the flow becomes turbulent.

MULTIPLE CHOICE QUESTIONS OF ENGINEERING DRAWING

1-The following is not included in title block of drawing sheet.

1. Sheet No
2. Scale
3. Method of Projection
4. Size of sheet

(Ans: d)

2-Which of the following represent reducing scale?

1. 1:1
2. 1:2
3. 2:1
4. 10:1

(Ans: b)

3-In first angle projection method, object is assumed to be placed in

1. First quadrant
2. Second quadrant
3. Third Quadrant
4. Fourth quadrant

(Ans: a)

4-The following line is used for visible outlines

1. Continuous thick
2. Continuous thin
3. Chain thin line
4. Short zigzag thin

(Ans: a)

5-The following line is used for dimension line

1. Continuous thick
2. Continuous thin
3. Chain thin line
4. Short zigzag thin

(Ans: b)

6-The dotted lines represents

1. Hidden edges
2. Projection line
3. Centre line
4. Hatching line

(Ans: a)

7-Hatching lines are drawn at ___ degree to reference line

1. 30
2. 45
3. 60
4. 90

(Ans: b)

8-In aligned system of dimensioning, the dimensions may be read from

1. Bottom or right hand edges
2. Bottom or left hand edges
3. Only from bottom
4. Only from left side

(Ans: a)

9-The Length:Width in case of an arrow head is

1. 1:1
2. 2:1
3. 3:1
4. 4:1

(Ans: c)

10-Metric thread of 10mm diameter is represented by

1. 10M
2. M10
3. M^10
4. None of the above

(Ans: b)

11-The internal angle of regular pentagon is ___ degree.

1. 72
2. 108
3. 120
4. 150

(Ans: a)

12-The internal angle of regular hexagon is ___ degree.

1. 72
2. 108
3. 120
4. 150

(Ans: c)

13-‘Representative fraction’ (RF) is defined as

1. Length of an object in the drawing / Actual length of the object
2. Length of an object in the drawing / Isometric length of the object
3. Actual length of the object / Length of an object in the drawing
4. Isometric length of the object / Length of an object in the drawing

(Ans: a)

14-A line of 1 meter is shown by 1cm on a scale. Its Representative fraction (RF) is

1. 1
2. 100
3. 1/100
4. 1/50

(Ans: c)

15-A point ‘P’ is above Horizontal Plane (HP) and in front of Vertical Plane (VP). The point is in

1. First quadrant
2. Second quadrant
3. Third quadrant
4. Fourth quadrant

(Ans: a)