Engineering - Exam Papers - OL - Paper - 2003

200 Marks
Answer Question 1, Sections A and B and THREE other questions.

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1.

(65 Marks)

Section A - 30 Marks
Give brief answers to any six of the following :

(a)	List two safety precautions to be observed when using an electric strip heater to bend plastics.
(b)	What do the letters LED stand for in electronic circuits?
(c)	Name two types of hard soldering.
(d)	Name the metals derived from the following ores: (a) Galena; (b) Bauxite.
(e)	What is the essential difference between a plotter and a printer?
(e)
(f)	Name the plastics used to produce (i) a Gear Wheel and (ii) a 3-Pin Plug.
(g)	Name two types of screw thread.
(h)	Name two electrical measuring instruments.

Section B - 35 Marks
Answer any three of the following :

(i)	Describe the function and operation of any one of the following: Feeler gauge, Single acting pneumatic cylinder, Light Dependent Resistor (LDR).
(j)	Explain any two of the computing terms: CD-ROM, Graphics Card, Software, Formatting.
(k)	Define ductility in relation to the properties of metals and give one example of a ductile metal.
(l)	Explain any two of the terms: Knurling, Enamelling, Conductor, Reaming.
(m)	Name the two cutting tools shown:
(m)

2.

(45 Marks)

(a)	Name the metals produced in the following furnaces:
	(i)	Cupola;
	(ii)	Blast Furnace;
	(iii)	Electric Arc Furnace;
	(iv)	Basic Oxygen Furnace.
(b)	What is the essential difference between ferrous and non-ferrous metals and give one example of each?
(c)	Name the materials used to manufacture:
	(i)	Bit of a soldering iron;
	(ii)	TV aerial;
	(iii)	Scriber.
(d)	State one industrial application for lead.

3.

(45 Marks)

(a)	Name three different methods used in the heat treatment of steel.
(b)	Describe the carburising process for case-hardening mild steel components.
(c)	Explain the effect of heat treatment on copper.
(d)	(i)	Explain hardness in relation to the properties of metals.
	(ii)	What is work hardening?
OR
(d)	Explain how the pneumatic circuit shown operates and give an example of the use of such a circuit.

4.

(45 Marks)

(a)	Identify the three types of oxyacetylene flame below:

(b)	How is protection from oxides achieved during electric arc welding?
(c)	Name the process use for making a permanent joint in each of the following materials:
	(i)	Light gauge aluminium;
	(ii)	Tinplate;
	(iii)	Mild steel plate.
(d)	Name two safety precautions to be taken when operating electric arc welding equipment.
OR
(d)	Sketch the symbols for the following components in an electrical circuit:
	(i)	Buzzer;
	(ii)	LED;
	(iii)	Motor.

5.

(45 Marks)

(a)	Explain the following terms associated with the technology of plastics:
	(i)	Thermosetting;
	(ii)	Thermoplastic.
(b)	Name three industrial manufacturing processes for producing articles from plastics.
(c)	Describe one process from (b) above, with the aid of a diagram, and identify the article produced.
(d)	Name a plastic used in the manufacture of insulation.

6.

(45 Marks)

(a)	Identify the turning operations shown:

(b)	Explain the necessity for clearance and rake angles on a lathe cutting tool.
(c)	Name three methods of taper turning on the centre lathe and explain one method with the aid of a diagram and note.

7.

(45 Marks)

(a)	A shaft is made to the following dimensions 80mm ± 0.05. State the
	(i)	Nominal Diameter;
	(ii)	Upper Limit;
	(iii)	Lower Limit;
	(iv)	Tolerance.
(b)	Explain the following:
	(i)	Clearance fit;
	(ii)	Interference fit.
(c)	Name the gauges shown and explain their function in relation to limits and fits.

OR
(c)	Explain a function for the circuit shown and what purpose the transistor serves?