# HELP: Phy6 QuestionWatch

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#1
Need some urgent help:
Jan2003 phy6:
Q4 (a) (iii)

show that the power transfered to the conducting link of resitance R in WXYZ circuit can be shown by :

P = v^2R/(R+r)^2

the circuit is 2 parallel railway lines connected at ends WZ by conducting link of resitance R. An axle, XY of resitance r is rolled along them. V is an induced emf.
TIA.
0
14 years ago
#2
Hey its just some rearranging (going 2 write e.m.f as E)

P=IV

E = I (R + r)
I = E / (R + r)
and V = IR

P = E / (R+r) *IR
= E/ (R+r) * ER/(R+r)
= E^2R/(R+r)^2

Hope it makes sense!
0
#3
cheers. makes perfect sense now.
0
14 years ago
#4
Yeah since u posted this question Intercity125, I was working on it...but not getting it...thanks ktc, puts my mind to rest aswell!
0
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