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Determine the equivalent resistance of the circuit

  • Thread starter zelda1850
  • Start date
  • #1
66
0

Homework Statement



a 3.0 ohm resistor an unkown resistor r and two ammeters a1 and a2 are connected with a 12 volt source ammeter a2 reads a current of 5.0 amperes

1) detemine the equivalent resistance of the circuit
2) caculate the current measure of ammeter a 1
3) caculate the resistance of the unknown resistor r


Homework Equations



v= 12 v
a2 = 5.0 a
a1 = ?
r1 = 3.0 ohm
r2 =?

this is a parallel circuit so

do i use v/a to find equivalent resistance?

for current do i use v/r to find a?

and for the resistor is this equation right 1/req = 1/r1 + 1/r2

The Attempt at a Solution



i got 2.4 ohm for the equivalent resistance and 4 a for the current dont know if it right
 

Answers and Replies

  • #2
1,953
248
There's no way to answer this without seeing the circuit.
 
  • #3
66
0
oh here a picture of the diagram for the problem

o938s4.jpg
 
  • #4
Cyosis
Homework Helper
1,495
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The answers you have so far are correct. What exactly makes you doubt your solution?
 
  • #5
69
0
You are correct so far, so why not go on to find the resistance of the unknown resistor using the formula you have: [tex]\frac {1}{R_{eq}} = \frac{1}{R_{1}} + \frac{1}{R_{2}}[/tex]
 
  • #6
66
0
ok i got 12 r for the resistor using that equation
 
  • #7
69
0
ok i got 12 r for the resistor using that equation
Which is correct, apart from the units; the units of resistance are Ohms, [tex]\Omega[/tex].
 

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