waecE-LEARNING
Metal Works Paper 2, Nov/Dec. 2011  
Questions: 1 2 3 4 5 Main
General Comments
Strength
Weakness/Remedies









Question 3

(a)        (i)         State the purpose of investigation in design.
(ii)        List three methods of carrying out investigation.

(b)        State the difference between passive and active fluxes.

(c)        List two examples each of:
(i)         passive flux;
(ii)        active flux.

(d)        With the aid of a sketch, describe how two metals are joined together using countersunk head rivets.

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OBSERVATION

This question was one of the most difficult question for the candidates.  Parts (a), (b) and (c) were extremely difficult for the candidates.  The required responses to these parts are:

(ai)       The purpose of investigation in design is to provide the designer with required information about the design specification.

(aii)      Methods of carrying out investigation are:

-           observation;
-           interview;
-           literature review;
-           experiment;
-           questionnaire.

(b)        The difference between passive flux and active flux is that passive flux only protects the cleaned surface while active flux cleans and protects the surface.
(c)        (i)         Examples of passive flux are:
-           resin;
-           tallow.

(c)        (ii)        Examples of active flux are:
            -           Hydrochloric acid;
-           zinc chloride;
-           sal ammoniac.

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