WAEC Air Conditioning(Ac)/Rerigeration May/June 2015 Questions and Answers.
(a) State two advantages of a domestic absorption system over a vapour compression system.
(b) State four properties of a good refrigerant.
(c) Explain Charles’ law.
The candidates were able to answer the questions correctly. The marks scored by the candidates were above average.
(a) Sketch the following hand tools:
- junior hacksaw.
(b) State the function of one of the tools sketched in 2(a).
(c) Convert – 400F to 0C.
(d) List four types of load that constitute the total load in a cold store.
- The candidates showed poor drawing skills, scores in the drawings were below average.
The expected response is:
2. (a) (i) MALLET
(ii) DOT – PUNCH
(iii) JUNIOR HACK SAW
(a) List five types of refrigerant control.
(b) Sketch the refrigerant control used for a domestic refrigerator.
(c) With aid of a labelled sketch, show a vapour compression refrigeration cycle.
The candidates were able to identify the application of airconditioning and refrigeration components and were able to draw correctly the vapour refrigeration cycle.
(a) List four safety wears found in a refrigeration and airconditioning workshop.
(b) Define the following terms:
(ii) latent heat;
(iii) sensible heat.
(c) Sketch a Fahrenheit scale thermometer and indicate the freezing and boiling points of water.
- The candidates were able to identify and distinguish between concepts, they identified the right safety wears. They were able to define the terms and also gave a good representation of the Fahrenheit scale thermometer.
(a) Define an entrepreneur.
(b) State five characteristics of sole proprietorship.
(c) Explain the term overdraft.
The candidates were able to answer the questions correctly, they related their answers to Airconditioning and Refrigeration trade.
The paper was of the right standard and the questions were within the scope of the syllabus, well arranged and composed. The performance of the candidates this year was better than the performance of the previous year. The highest score last year was 42/60, while this year was 49/60.
Candidates’ Weakness and Suggested Remedies
Candidates possessed poor computation skills. About five candidates attempted the question on calculations but only one of them got it right.
(2) SUGGESTED REMEDIES FOR OVERCOMING WEAKNESSES
The following were the suggestion made if the weaknesses are to be remedied:
- teachers should intensify efforts to teach the students more calculations in the trade.
- students should study the calculation aspect of the trade to compliment the efforts of the teacher.
The candidates did very well on the questions requiring them to recall facts.