- #1

Clara Chung

- 304

- 14

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## Homework Statement

## Homework Equations

Please review the question and answer of question 34.

## The Attempt at a Solution

1.Why does the answer take the rated power as the power output?

2.I tried to find the current like this:

R=200^2 / 100 = 400 ohm

I at Q = 400/[2(400)] = 0.5 A

I at P = 0.5/2 = 0.25 A

3. As the approach as shown as (2) is wrong. Either V is not equal to IR in the circuit Q or the secondary voltage is not 400/2 = 200V.

4. As question 36 used a similar method as (2), V should be equal IR. So the only possibility is Vq not equal to Vp [Nq/Np].

5. However as the change of magnetic flux is the same everywhere in the iron core. By V=-NdΦ/dt.

Vp=- Np dΦ/dt...(a)

Vq=- Nq dΦ/dt...(b)

Vr=- Nr dΦ/dt...(c)

by (b)/(a)

Vq = Vp [Nq/Np]

6. So please tell me what's wrong. Thank you VERY much.