Fundamental of Welding Science and Technology NPTEL ANSWERS : WEEK 7

Fundamental of Welding Science and Technology NPTEL ANSWERS : WEEK 7

THE ANSWERS ARE TAKEN FROM ONLINE SOURCES LIKE YOUTUBE VIDEOS AND GOOGLE SEARCH

1. In SMAW, it should be limited to weaves not exceeding

 1and1/2 times the diameter of the electrode

 2and1/2 times the diameter of the electrode

 3and1/2 times the diameter of the electrode

 4and1/2 times the diameter of the electrode

B

1 point

2. Rutile electrode contains high proportion of:

 Calcium carbonate

 Tungsten oxide

 Titanium oxide

 Calcium oxide

C

1 point

3. In oxy-fuel gas welding the acetylene gas shouldn’t be used at a pressure greater than:

 255 kPa

 155 kPa

 105 kPa

 55 kPa

C

1 point

4. Which of the chemical compounds form Basic electrodes?

 CaCO2 + CaF2

 C2H2 + CaCO3

 CaCO3 + CaF2

 C3H3 + CaCO3

C

1 point

5. Which type of electrode is most prone to H2 embrittlement?

 Rutile electrode

 Cellulosic electrode

 Basic electrode

 Metal powder electrode

 (NOT SURE)

1 point

6. The cylinder colour of Acetylene gas cylinder used in Oxy-Fuel gas welding is:

 Black

 Blue

 White

 Maroon

D

1 point

7. In SMAW, which type of electrode is preferable for either polarity & all positions?

 Rutile Electrode

 Cellulosic Electrode

 Metal Powder Electrode

 None of these

A

1 point

8. Between the neutral and oxidizing flame which one has the maximum peak temperature?

 Both have same

 Neutral flame

 Oxidizing flame

 None of these

C

1 point

9. In neutral flame the ratio of oxygen to acetylene is

 greater than 1.5

 greater than 1.0

 equal to 1.0

 equal to 1.5

C

1 point

10. In oxygen/acetylene welding, the oxygen uses for combustion in the first stage is supplied from

 the atmosphere

 the oxygen cylinder

 the C2H2 cylinder

 all the above

B

THE ANSWERS ARE TAKEN FROM ONLINE SOURCES LIKE YOUTUBE VIDEOS AND 

GOOGLE SEARCH

Fundamental of Welding Science and Technology NPTEL ANSWERS : WEEK 6 (Question 7-8)

 Fundamental of Welding Science and Technology NPTEL ANSWERS : WEEK 6 (Question 7-8)

7. Increase in welding current tends to cause:

 More distortion

 Less distortion

 More reinforcement

 Both (a) and (c)

D

8. In a DC arc welding operation, the voltage-arc length characteristic was obtained as Varc = 20 + 5*l, where the arc length l was varied between 5 mm and 7 mm. Here Varc denotes the arc voltage in Volts. The arc current was varied from 400 A to 500 A. Assuming linear power source characteristic, the open circuit voltage and the short circuit current for the welding operation are:

 45 V, 450 A

 75 V, 750 A

 95 V, 950 A

 150 V, 1500 A

C

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Fundamental of Welding Science and Technology NPTEL ANSWERS : WEEK 6 (Question 5-6)

 Fundamental of Welding Science and Technology NPTEL ANSWERS : WEEK 6 (Question 5-6)

5. With the decrease of electrode extension:

 Electrical resistance decreases

 Bead width increases

 More forceful arc

 All three options (a, b, and c) are correct

D

Electrode extension, also known as length of stick out, is the distance between the end of the contact tube 

and the end of the electrode. 

 An increase in electrode extension results in an increase in electrical resistance. 

 This causes resistance heating of electrode extended length, 

resulting in additional heat generation and increase of electrode melting rate. 

 But the energy so consumed reduces the power delivered to the arc thus decreases

 bead width and penetration depth.

1 point

6. Effect of welding speed (w) on melting efficiency?

 With increase of w, melting efficiency increase

 With decrease of w, melting efficiency increase

 W has no effect on melting efficiency

 All of these

A

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Fundamental of Welding Science and Technology NPTEL ANSWERS : WEEK 6 (Question 9-10)

 Fundamental of Welding Science and Technology NPTEL ANSWERS : WEEK 6 (Question 9-10)

9. In case of arc welding of steel with a potential of 20 V and current of 200 A, the travel speed is 5 mm/s and the cross-sectional area of the joint is 20 mm^2. The heat required for melting steel may be taken as 10 J/mm^3 and heat transfer efficiency as 0.85. The melting efficiency will be nearly:

 18 %

 29 %

 36 %

 42 %

B (NOT SURE)

1 point

10. A direct current welding machine with a linear power source characteristic provides open circuit voltage of 80 V and short circuit current of 800 A. During welding the machine, the measured arc current is 500 A corresponding to an arc length of 5.0 mm and the measured arc current is 460 A corresponding to an arc length of 7.0 mm. the linear voltage (E)-arc length (L) characteristic of the welding arc can be given as (where E is in volt and L is in mm)?

 E = 80 + 8L

 E = 80 + 2L

 E = 20 + 8L

 E = 20 + 2L

D

Fundamental of Welding Science and Technology NPTEL ANSWERS : WEEK 6 (part 2)

Fundamental of Welding Science and Technology NPTEL ANSWERS : WEEK 6 (Question 3-4)

WEEK 7 ASSignMENT

PART 1

3. An acetylene/oxygen flame burns at ___ °C.

 2,250

 2,526

 3,073

 3,773

        D (NOT SURE)

4. In oxygen/acetylene welding for the complete combustion of C2H2:

 1/5th proportion of the O2 comes from the cylinder

 2/5th proportion of the O2 comes from the cylinder

 3/5th proportion of the O2 comes from the cylinder

 5/5th proportion of the O2 comes from the cylinder

 B

As the oxygen-acetylene mixture burns from the tip of the welding torch, it displays several 

clearly recognizable zones of combustion.

The overall chemical equation for the complete combustion of acetylene is: 

 2C2H2 + 5O2 ----->  4CO2 + 2H2O ............................................(1) 

NEXT ANSWER

1 point

NPTEL EXAM PATTERN AND TIPS 2023

 NPTEL EXAM PATTERN AND TIPS 2022

NTPEL Exam Pattern – Hello learners, in this blog I am going to share the NTPEL EXAM PATTERN 2023. The information in this blog is verified and the latest information for NPTEL EXAM PATTERN 2023.

NPTEL is a short form of the National Program on Technology Enhanced Learning and it comes under Massive open online courses(MOOC), this program is run by the Government of India and has been running since 2007. NPTEL is an initiation run or Partner by the IITs and IISc Bangalore and is funded by the Ministry of Human Resource Development, Government of India.

NPTEL is a good and free online learning platform for students across India to get mentorship from the Professors of India’s elite institute for free, certification from NPTEL is widely accepted all over the country.

How to Crack NPTEL EXAM PATTERN?

My previous experience led me to the following conclusion about the exam pattern:

NPTEL Exam is totally based on your course type but mostly questions are MCQ based only with some  Numerical Answer Type or fill in the blanks type and Definition Questions.

From experience NTPEL Exam Pattern are mostly Assignment based questions 60% of questions will be similar to weekly quiz assignments and the rest 40% will be conceptual directly taken from video lectures.

The level of questions are basic to intermediate not very tough, if you have gone through the lectures it will be very easy.

What is NPTEL EXAM PATTERN FOR 2023

NPTEL EXAM PATTERN 2022

Total marks – 100

Duration- 3hrs, but if you have finished the exam early you can leave after half time (90 minutes) .

The number of questions in each section will depend on your course and obviously on the professor who is setup Exam the question paper.

Case-1:- If your course has an online programming test
Final exam marks will be – 75marks

Case-2:- If your course does not have an online programming test
Final exam marks – 100

2. No Negative marking
3. Contains 3 sections(mostly MCQ)
   Section 1 – 2 marks
   Section 2 – 2 marks
   Section 3 – 2.5 marks or 3 marks

Most of the questions are MCQ based with some fill in the blanks or Numerical answer type and definition questions

*Mostly there will be a set of 55 questions.

Note:- There is no fixed number of questions.

NPTEL EXAM PREPRATION TIPS –

First of all, keep in mind NPTEL EXAM is not a very tough exam, getting the certification of NPTEL is very easy if you have gone through video lectures and assignments. But how to pass NPTEL exam without studying even if you have not gone through the all lectures you can still pass the exam.

NPTEL FINAL EXAM TIPS:-

How to pass NPTEL exam in one day

1. Make sure to do all the MCQ assignments(80% ques are from assignments only, not exactly same but similar)
2. If you have time then watch videos of any 4 weeks(preferably middle weeks and go through their assignment by yourself)
3. If your course had provided assignment solution then take any 4 weeks and read that detailed assignment.
4. Don’t leave any que in exam.

Note:- Above steps are not much recommend but if you have not studied for the exam at all and want to do last-minute preparation then you can try this method.

All the best for your exam.

Frequently Asked Questions – NPTEL EXAM PATTERN

NPTEL EXAM conducted at the center or at home?

NPTEL FINAL EXAM is the center-based exam you have to appear in person and take the exam. The duration of the exam is 3hrs and if you want you can leave after half time.

Is there any negative marking in NPTEL FINAL EXAM?

No, there is no negative marking in the final exam you can attempt all the questions.

Where I can download NPTEL admit card?

You can visit the official site of NPTEL and download your admit card or a separate mail will be sent to you with the link of admit card.

Where to get NPTEL FINAL EXAM Question papers?

NPTEL doesn’t disclose final exam questions after the exam so you can’t find them anywhere but questions are mostly assignment-based.

Is the programming question will be in NPTEL FINAL EXAM?

No, there will be no programming questions in the final exam, no IDE will be provided question will be MCQ, And fill in the blanks.

Fundamental of Welding Science and Technology NPTEL ANSWERS : WEEK 5 (2)

 

Fundamental of Welding Science and Technology NPTEL ANSWERS : WEEK 5

PART 2                        FOR PART 1 CLICK HERE

ASSIGNMENT 6 CLICK HERE

1 point

6. Electromagnetic force doesn’t play any role in:

 Projected metal transfer

 Rotating metal transfer

 Streaming metal transfer

 Metal transfer from filler wire

D                     LECTURE 2

1 point

7. Surface tension force is the main governing force for which of the mode of metal transfer?

 Projected metal transfer

 Rotating metal transfer

 Streaming metal transfer

 Bridging metal transfer

D                       LECTURE 2

1 point

8. In explosive metal transfer the main governing force/forces

 is electromagnetic force only

 is surface tension force only

 are electromagnetic force and chemical reactions

 are surface tension force and chemical reactions

C                    LECTURE 2

1 point

9. Projected spray metal transfer occurs

 at a current which is less than streaming spray metal transfer current

 at a current which is more than globular type metal transfer current

 at a current which is less than rotating spray metal transfer current

 all of these

D                  LECTURE 2

1 point

10. The current at which the globular metal transfer converted to spray metal transfer is called welding the 

       ‘transition current’ refers to a current at which

 transfer current

 transmission current

 transition current

 none of these           

C        (NOT SURE because of question language)    LECTURE 2

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