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Electrical= Resistance and Energy

  • Thread starter Forceflow
  • Start date
30
0
A wire of resistance 9.0 is connected to a battery whose emf is 3.0 V and whose internal resistance is 1.0 .
(a) How much energy is transferred from chemical to electrical form in 4.0 min?
(b) How much energy appears in the wire as thermal energy in that time?

answer to a= 216 (that's correct)
for b, i got 189.629 (that one is wrong though)

For the work, i did: I= 3V/9 = .3333 A
Vtotal= 3V-IR
Vtotal= 3V-.333(1)
Vtotal= 2.6666
p=Vsquared/R
P=2.666 squared/9
P= .79011
.79011 (4) (60) = 189.62
 

Answers and Replies

131
0
When calculating the current -- why would you ignore the resistance of the battery? (Normally you would, but in this case it is a fairly high component of the overall resistance of the circuit)
 
30
0
i would ignore it because its asking for the energy in the wire specifically..i believe anyway
 
30
0
if for a new answer, i got 194.4 joules..would that be correct?
 
30
0
is 194.4 the answer?
 

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