Waec Model Questions Vol1 2024 Agricultural Science Question 12

Practice objective / multiple choice question 12 from the 2024 Waec Model Questions Vol1 Agricultural Science examination.

Waec Model Questions Vol1 2024 Agricultural Science Objective / Multiple Choice Hard Difficulty
Question 12 WAEC_MODEL_QUESTIONS_VOL1 • 2024 • AGRICULTURAL_SCIENCE • objective

A batch of 500 kg fresh cassava roots contains 60 % moisture (wet basis). After peeling and slicing, the chips are dried in a solar dryer. For the first period, while the moisture content is above 30 % (wet basis), the drying rate is constant at 2.5 kg of water removed per hour. Once the moisture content reaches 30 %, the drying rate drops to 1.2 kg of water per hour. Determine (a) the total drying time required to reduce the moisture content to 12 % (wet basis) and (b) the total energy needed for the whole drying operation, assuming the latent heat of vaporisation of water is 2260 kJ kg⁻¹. Express the drying time in hours (one decimal place) and the energy in kilojoules (nearest whole number).

Answer Options

A. 140.2 h, 640,000 kJ
B. 125.8 h, 610,000 kJ
Correct Answer C. 134.4 h, 616,364 kJ
D. 130.5 h, 590,000 kJ
Correct Answer
C
Correct Option:
134.4 h, 616,364 kJ

About This Question

This is Waec Model Questions Vol1 2024 Agricultural Science Question 12. It is one of the objective questions from the 2024 Waec Model Questions Vol1 Agricultural Science examination.

Difficulty level: Hard .

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