You are Here: Home

# Transformers Tweet

Physics exam discussion - share revision tips in preparation for GCSE, A Level and other physics exams and discuss how they went afterwards.

Announcements Posted on
IMPORTANT: You must wait until midnight (morning exams)/4.30AM (afternoon exams) to discuss Edexcel exams and until 1pm/6pm the following day for STEP and IB exams. Please read before posting, including for rules for practical and oral exams. 28-04-2013
1. Transformers

I am struggling on part (b), especially when adding two Zs together.
Attempted solution.
(a) \( Z_1 \) = 20 @ 0.8 lag = 20 cos^-1(0.8) = 20∠36.87 Ω
Z_2 = 20 @ 0.6 lead = 20 sin^-1(-0.6)=20∠-53.13 Ω

(b) When in series.
Z=Z_1+Z_2 = 20∠36.87 + 20∠-53.13
I don't know how to add these.

On another note: How do I write math code here?
Last edited by ashuto; 25-07-2012 at 16:41.
2. Re: Transformers
Extra: In which subsection does this problem fall into? You may chose only one. Note that you won't be given mark if you chose none but penalty may be given if the wrong answer is chosen.
a) Electric Fields
b) Current of Electricity
c) D.C. Circuits
d) Electromagnetism
e) Electromagnetism Induction
f) Alternating Current

What do you think?
3. Re: Transformers
Answer for b) is 28.28∠-8.13 ohm. I wonder how they get that. I tried to convert the polar into complex first but the answer is wrong.
Useful resources

## Articles:

Study Help rules and posting guidelinesStudy Help Member of the Month nominations

## Groups associated with this forum:

View associated groups