# A.C. Circuit

#### frozen7

An electric toaster draws 3A rms current from a 240V, 50Hz source. Calculate the average power and peak value of the instantaneous power to the toaster.

$$P(average) = I (rms) x V (rms) cos \phi$$

Since the power factor is not mentioned in the question. Can the question be solved?

Related Introductory Physics Homework News on Phys.org

#### berkeman

Mentor
If the power factor isn't given, it probably isn't needed. What would you guess the power factor of a toaster to be? What is the heating mechanism?

#### frozen7

Is it because all the energy become heat so the power factor is equal to one ?

#### berkeman

Mentor
Yeah. The heating element is purely resistive, and the power factor of a resistive circuit is unity. You only get a phase shift between the applied voltage and resulting current if the load is reactive.

"A.C. Circuit"

### Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving