Thursday, September 10, 2015

MCQ on Mechanical Energy Based Unconventional Machining Process


MCQ on Mechanical Energy Based Unconventional Machining Process

1.In abrasive jet machining, as the distance between the nozzle tip and the work surface increases, the material removal rate

a)increases continuously

b) decreases continuously

c) decreases, becomes stable and then increases

d) increases, becomes stable and then decreases

 

2.The size of abrasive grains in abrasive jet machining ranges from

a) 1 to 10 microns

b) 10 to 50 microns

c) 50 to 100 microns

d) 100 to 500 microns

 

3.The vibrating frequency used for the tool in Ultrasonic machining is of the order of

a) 10,000 oscillations per second

b) 35,000 oscillations per second

c) 35,000 oscillations per second

d) 45,000 oscillations per second

 

4.In Ultrasonic machining, the material is removed by

a) anodic dissolution

b) thermal melting

c) abrasive action

d) electrochemical oxidation

 

5.Ultrasonic machining can machine both metallic and non-metallic surfaces

a) True

b) False

 

6.Which of the following machining process(es) use mechanical energy as the principal energy source ?

a) conventional milling

b) water jet cutting

c) wire cut EDM

d) abrasive jet machining

 

 

7.Abrasives contained in a slurry are driven at a high velocity against the work by a tool vibrating at low amplitude and high frequency.This is the metal removing mechanism for__________________

a) USM

b) LBM

c) WJM

d) AJM

 

8.In USM, the amplitude of  vibrating tool is,

a) 10 - 50 micro meter

b) 500 - 5000 micro meter

c) 20 - 20000 micro meter

 

 

9.Which of the following material is not generally machined by USM

a) Copper

b) Glass

c) Silicon

d) Germanium

 

10.Tool in USM is generally made of

a) Glass

b) Ceramic

c) Carbides

d) Steel

 

11.Increasing volume concentration of abrasive in slurry (in USM process)  would affect MRR in the following manner

a) increase MRR

b) decrease MRR

c) would not change MRR

d) initially decrease and then increase MRR

 

 

12.In water jet cutting and abrasive water jet cutting, the separation between the nozzle opening and the work surface is called which one of the following

a) Gap

b) gap size

c) orifice

d stand-off distance

 

13.In abrasive water jet cutting, the abrasive particles are added to the water stream

after it exits the nozzle

a) before it enters the pumping unit

b) just before it enters the nozzle

c) while it is in the nozzle

 

14.AJM nozzles are made of

a) low carbon steel

b) HSS

c) WC

d) Stainless steel

 

15.Material removal takes place in AJM due to

a) electrochemical action

b) fatigue failure of the material

c) sparking on impact

d) mechanical impact

 

16.As the stand off distance increases, the depth of penetration in AJM

a) Increases

b) decreases

c) does not change

d) initially increases and then remains steady

 

 

17.Abrasive slurry is used in the following type of machining process.

a) Ultrasonic machining

b) Conventional milling

c) Wire cut EDM

d) Laser beam machining

 

18.The following principle is used for converting electrical energy into mechanical energy in USM

a) Faraday's law

b) Stefan's law

c) Piezoelectric effect

d) Thomson's law

 

19.The following device is used for converting electrical impulses into mechanical vibration in USM

a) Transducer

b) oscillator

c) tank

d) pump

 

20.In AJM, removal of metal takes place by bombardment of fine grained particle.

a) with air at high velocity

b) with water at high velocity

c) with kerosene at high velocity

d) at controlled rate in brine

 

21.In WJM, removal of metal takes place by bombardment of fine grained particle.

a) with air at high velocity

b) with water at high velocity

c) with kerosene at high velocity

d) at controlled rate in brine

 

22.WJM cannot be used to machine

a) frozen food

b) plywood

c) leather
d) steel plates

Friday, September 04, 2015

IAS 2015 Preliminary Question Analysis (General Studies - I)


UPSC IAS Prelims 2015: Paper Analysis

 

The Union Public Service Commission (UPSC) conducted the Civil Services preliminary exam on August 23, this year. Almost 4.56 lakh candidates appeared for the exam. The exam was segregated into two Parts: Part I (General Studies) and Paper II (CSAT/Aptitude Test). The exam was held at 2,186 venues in 71 centres. 

Experts reviewed the paper and have come up with the following analysis:

1.There was diversity in the questions asked

Sl.No.
Subject / Area
No. of questions asked
1.
Geography-17
17
2.
Environment-6
6
3.
History-13
13
4.
Art & Culture-4
4
5.
Politics- 12
12
6.
Government Schemes-6
6
7.
Economics-10
10
8.
Science & Technology- 8
8
9.
Current Affairs- 16
16
10.
International Organisations- 8
8
Total
100

 

2.Current Affairs has gained prominence, thereby making it essential for the candidates to read newspapers

3.Focus was laid on areas such as Environment, Government Schemes & International Organisations 

4.Clarity of basic concepts in various topics should be the focus of students preparing for this exam

5.Overall the paper was not very tough for those who had done detailed and systematic preparation

For students who appeared for Civil Service Preliminary Examination (2015), General Studies Paper-I has become crucial because it is the decisive paper for selection in the Main examination, this year onward. CSAT Paper has been made of qualifying nature with minimum passing marks of 1/3rd of the total marks. 

The preliminary examination consisted of objective type (multiple choice questions) each paper of 200 marks, carrying a total of 400 marks. The question papers were set both in Hindi and English. The blind candidates are permitted extra time of 20 minutes for each paper. 

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Wednesday, September 02, 2015

MCQ on Automatic & Semi-Automatic Lathes, Gears


1.Automatic lathes are machine tool, in which work pieces are loaded manually.

a)True                                     b)False

 

2.Choose the correct statement(s) about automatic lathes.

a) High production rate

b) High accuracy

c) High labour fatigue

d) More labour cost

 

3.In automatic lathes, there is less production time

a) True                                    b) False

 

4.Semi-automatic lathes are suitable for large size components

a)True                                     b) False

 

5.In a parallel action multi spindle automatic lathes, different kind of operation carried out on the same workpiece

a) True                                    b) False

 

6.In a multi-spindle automatic lathes, number of spindles are vary from

a) 2 to 8

b) 2 to 6

c) 2 to 10

d) 2 to 4

 

7.Automatic lathes are suitable for small size components

a) True                                    b) False

 

8.In a progressive action multi spindle automatic lathes, same operation carried out on all the spindles

a) True                                    b) False

 

9.Choose the correct statement (s) about single spindle automatic lathe

a) There is only one spindle

b) High production rate

c) Higher machining accuracy

d) Only one work piece is machined at a time

 

10.Choose a correct statement(s), about multi-spindle automatic lathe

a) Lower machining accuracy

b) Tool setting time is more

c) High production rate

d) Economical for longer runs only

 

11.In automatic lathes, cams are used for power transmission

a) True                                    b) False

 

12.Parallel action multi-spindle machine are suitable for machining complicated shapes

a) True                                    b) False

 

13.Production rate is very high in parallel action multi-spindle machine

a) True                                    b) False

 

14.Transfer machines are those used to indexing the tool regarding to the operation

a) True                                    b) False

 
15.Choose the correct statement(s) about transfer machines

a) only suitable for mass production

b) workpieces are clamped in fixtures

c) less floor space is required

d) less production time

 

16.Gear broaching is mainly used for producing external gears

a) True                                    b) False

 

17.For finishing a hardened gears, which method is/are used

a) gear grinding

b) gear lapping

c) gear burnishing

d) gear shaving

 

18.Choose the odd one out

a) Gear broaching

b) Gear shaping

c) Gear hobbing

d) Gear burnishing

 

19._________________Gears are self-lubricating

a) Nylon

b) Fibre

c) Brass

d) Bronze

 

20.The gear finishing method typically performed prior to heat treatment is:

a) Honing

b) continuous grinding

c) form grinding

d) shaving

 

21.The rolling action between engaging gear teeth is due to:

a. high viscosity lubricants

b. points of tangency between teeth

c. the involute curve form

d. gear rotational synchronization

 

22. The imaginary rolling circle produced by meshed gears during rotation is called the:

a. Pitch Circle

b. Base Circle

c. Dedendum Circle

d. Addendum Circle

 

23. The most common type of gear is the:

a. spur gear

b. helical gear

c. straight bevel gear

d. hypoid gear

 

24. A worm gear is an example of a gear type used along:

a. parallel axes

b. non-intersecting, non-parallel axes

c. connecting axes

d. intersecting axes

 

25. The most common gear manufacturing method is:

a. forging

b. machining

c. injection molding

d. stamping

 
26. Hobbing is used to produce only:

a. helical gears

b. spur gears

c. external gear teeth

d. internal gear teeth

 

27. Gear form cutting involves the use of:

a. hobbing and shaping

b. shaping and milling

c. multiple stacked blanks

d. broaching and milling

 

28. The gear finishing method typically performed prior to heat treatment is:

a. honing

b. continuous grinding

c. form grinding

d. shaving