An alternating current having a peak value \(14~\text A\) is used to heat a metal wire. To produce the same heating effect, a constant current \(i\) can be used, where the value of \(i\) is:
1. \(14~\text A\)
2. about \(20~\text A\)
3. \(7~\text A\)
4. about \(10~\text A\)
An AC source rated \(100~\text{V}\) (rms) supplies a current of \(10~\text{A}\) (rms) to a circuit. The average power delivered by the source:
(a) | must be \(1000~\text{W}\). |
(b) | may be \(1000~\text{W}\). |
(c) | may be greater than \(1000~\text{W}\). |
(d) | may be less than \(1000~\text{W}\). |
1. | (a) only |
2. | (b), (c) |
3. | (b), (d) |
4. | (a), (d) |