Engineering - Exam Papers - OL - Paper - 1994
200 Marks
Answer Question 1, Sections A and B and THREE other questions.
Structure | TEDs | Plastics | Metallurgy | Metrology | Steels & Iron | Information Tables | Exam Papers | Syllabus
1.
(65 Marks)
Section A - 30 Marks
Give brief answers to any six of the following :
| (a) | Give an example of a malleable metal. |
| (b) | What is meant by capillary action? |
| (c) | What is the purpose of cryolite in the production of aluminium? |
| (d) | Explain the essential difference between breadboard and veroboard. |
| (e) | List two reasons for using a cutting fluid when machining. |
| (f) | Name the thread form suitable for : (i) A Lathe leadscrew; (ii) A quick-release vice. |
| (g) | Define interference as used in a system of limits and fits. |
| (h) | Name two types of electrical circuit. |
Section B - 35 Marks
Answer any three of the following :
| (i) | Describe the function and operation
of any one of the following : (i) double-acting cylinder; (ii) solenoid; (iii) rack and pinion. |
| (j) | Explain any two of the computing terms : floppy disk; hardware; parallel port; plotter. |
| (k) | Explain the function of a light-dependent resistor (LDR). |
| (l) | Explain any two of the terms : PCB, spur gear, feeler gauge, resistor, insulator. |
| (m) | Explain how a quick-release vice operates. |
2.
(45 Marks)
| (a) | What process is carried out using
the open hearth furnace? With the aid of a sectional diagram, explain the process. |
|
| (b) | State two differences between hot-rolling and cold-rolling of steel. | |
| (c) | What is galvenised iron? State two applications. | |
3.
(45 Marks)
| (a) | Give two reasons for the heat treatment of non-ferrous metals. | |
| (b) | Explain why low carbon steel may be case-hardened rather than hardened. | |
| (c) | Explain one of the following terms used in the heat treatment of steel: | |
| (i) | recalescence; | |
| (ii) | critical temperature. | |
4.
(45 Marks)
| (a) | State the approximate composition of any two of the following: | |
| (i) | tinman's solder; | |
| (ii) | plumber's solder; | |
| (iii) | silver solder; | |
| (iv) | brazing spelter. | |
| (b) | Metals to be soldered must be chemically
clean. What does this mean? Hence, explain the essential difference between corrosive and non-corossive fluxes. |
|
| (c) | Name three of
oxy-acetylene flame. Which type is most suitable for welding 1.5mm steel sheet? |
|
5.
(45 Marks)
| (a) | Explain three methods used to join plastics. | |
| (b) | Describe the process of compression moulding. | |
| (c) | Name the plastic used for any two of the following applications: | |
| (i) | damp proof course used in the building industry; | |
| (ii) | cavity wall insulation; | |
| (iii) | ash tray; | |
| (iv) | plant pot. | |
| In each case, state whether the plastic is thermosetting or thermoplastic. | ||
6.
(45 Marks)
| (a) | Explain the term clearance in connection with cutting tool design. Illustrate your answer with a sketch of a lathe cutter. | |
| (b) | Explain two of the following: | |
| (i) | Compound slide; | |
| (ii) | Combination drill; | |
| (iii) | Knurling tool. | |
| (c) | List three safety precautions to be observed when using a centre lathe. | |
OR |
||
| (c) | Explain three of the following terms associated with the CNC lathe, using simple line diagrams to illustrate your answer: | |
| (i) | X and Y axis; | |
| (ii) | absolute measurement; | |
| (iii) | peck drilling; | |
| (iv) | grooving cycle. | |
7.
(45 Marks)
| (a) | Explain: | ||||
| (i) | bilateral tolerance; | ||||
| (ii) | unilateral tolerance. | ||||
| (b) | The limits of a hole and shaft assembly are shown in the table. | ||||
|
|||||
| Determine: | |||||
| (i) | The tolerance on each part; | ||||
| (ii) | The maximum allowance; | ||||
| (iii) | The minimum allowance; | ||||
| (iv) | The type of fit. | ||||
OR |
|||||
| (b) | The circuit shown is used
as a continuity tester. Explain the function of each of the following: |
||||
| (i) | the resistors; | ||||
| (ii) | the buzzer; | ||||
| (iii) | the contacts; | ||||
| (iv) | the transistor. | ||||
 |
|||||