Question
One air fryer for sale takes in 239 Joules of energy to cook a meal and has an efficiency of 80%. How much energy will be emitted when cooking this meal? (1 point)
158 J
298.8 J
47.8 J
191 J
158 J
298.8 J
47.8 J
191 J
Answers
GPT-4o mini
To find the energy emitted while cooking the meal with the air fryer, we need to calculate the amount of energy that is not converted into useful work (cooking the meal).
1. The total energy taken in is 239 Joules.
2. The efficiency of the air fryer is 80%, which means that 80% of the energy is used for cooking.
First, we calculate the useful energy output (energy used for cooking):
\[
\text{Useful energy output} = \text{Total energy} \times \text{Efficiency}
\]
\[
\text{Useful energy output} = 239 \, \text{J} \times 0.80 = 191.2 \, \text{J}
\]
Next, to find the energy emitted (which is the energy that is not used for cooking), we subtract the useful energy output from the total energy:
\[
\text{Energy emitted} = \text{Total energy} - \text{Useful energy output}
\]
\[
\text{Energy emitted} = 239 \, \text{J} - 191.2 \, \text{J} = 47.8 \, \text{J}
\]
Thus, the amount of energy emitted when cooking the meal is **47.8 J**.
**Correct Answer: 47.8 J**
1. The total energy taken in is 239 Joules.
2. The efficiency of the air fryer is 80%, which means that 80% of the energy is used for cooking.
First, we calculate the useful energy output (energy used for cooking):
\[
\text{Useful energy output} = \text{Total energy} \times \text{Efficiency}
\]
\[
\text{Useful energy output} = 239 \, \text{J} \times 0.80 = 191.2 \, \text{J}
\]
Next, to find the energy emitted (which is the energy that is not used for cooking), we subtract the useful energy output from the total energy:
\[
\text{Energy emitted} = \text{Total energy} - \text{Useful energy output}
\]
\[
\text{Energy emitted} = 239 \, \text{J} - 191.2 \, \text{J} = 47.8 \, \text{J}
\]
Thus, the amount of energy emitted when cooking the meal is **47.8 J**.
**Correct Answer: 47.8 J**