A model device receives 100 J and transfers 70 J as its intended useful output. The design target is at least 60% useful-output efficiency. Does this trial meet the target?
Answer & why
Answer: Yes, it meets the target.
Useful-output efficiency = 70/100 × 100 = 70%. Compare this with 60%; yes, it meets the target.
A model device receives 80 J and transfers 60 J as its intended useful output. The design target is at least 70% useful-output efficiency. Does this trial meet the target?
Input energy and useful output must be added to find efficiency.
The efficiency is always 100%.
Yes, it meets the target.
No, it falls below the target.
A hint
Divide the intended useful output by the energy input, then compare with the target.
Answer & why
Answer: Yes, it meets the target.
Useful-output efficiency = 60/80 × 100 = 75%. Compare this with 70%; yes, it meets the target.
A model device receives 150 J and transfers 90 J as its intended useful output. The design target is at least 70% useful-output efficiency. Does this trial meet the target?
No, it falls below the target.
Input energy and useful output must be added to find efficiency.
Yes, it meets the target.
The efficiency is always 100%.
A hint
Divide the intended useful output by the energy input, then compare with the target.
Answer & why
Answer: No, it falls below the target.
Useful-output efficiency = 90/150 × 100 = 60%. Compare this with 70%; no, it falls below the target.
A model device receives 120 J and transfers 96 J as its intended useful output. The design target is at least 75% useful-output efficiency. Does this trial meet the target?
Yes, it meets the target.
No, it falls below the target.
Input energy and useful output must be added to find efficiency.
The efficiency is always 100%.
A hint
Divide the intended useful output by the energy input, then compare with the target.
Answer & why
Answer: Yes, it meets the target.
Useful-output efficiency = 96/120 × 100 = 80%. Compare this with 75%; yes, it meets the target.
A model device receives 50 J and transfers 30 J as its intended useful output. The design target is at least 65% useful-output efficiency. Does this trial meet the target?
Input energy and useful output must be added to find efficiency.
Yes, it meets the target.
The efficiency is always 100%.
No, it falls below the target.
A hint
Divide the intended useful output by the energy input, then compare with the target.
Answer & why
Answer: No, it falls below the target.
Useful-output efficiency = 30/50 × 100 = 60%. Compare this with 65%; no, it falls below the target.
A model device receives 100 J and transfers 70 J as its intended useful output. The design target is at least 60% useful-output efficiency. Does this trial meet the target?
Yes, it meets the target.
No, it falls below the target.
The efficiency is always 100%.
Input energy and useful output must be added to find efficiency.
A hint
Divide the intended useful output by the energy input, then compare with the target.
Answer & why
Answer: Yes, it meets the target.
Useful-output efficiency = 70/100 × 100 = 70%. Compare this with 60%; yes, it meets the target.
A model device receives 200 J and transfers 120 J as its intended useful output. The design target is at least 65% useful-output efficiency. Does this trial meet the target?
The efficiency is always 100%.
Yes, it meets the target.
Input energy and useful output must be added to find efficiency.
No, it falls below the target.
A hint
Divide the intended useful output by the energy input, then compare with the target.
Answer & why
Answer: No, it falls below the target.
Useful-output efficiency = 120/200 × 100 = 60%. Compare this with 65%; no, it falls below the target.
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