Calculate the equivalent resistance

Sylvia
Messages
30
Reaction score
1

Homework Statement


screen_shot_2015-02-01_at_1.34.51_pm.png

Ignore the internal resistance of the battery and assume it is merely a battery. Calculate the equivalent resistance of the circuit.

Homework Equations


1/Req = 1/R + 1/R ... (parallel)
Req = R + R ... (series)

The Attempt at a Solution


I know this is fairly simple but I don't understand how you would calculate the equivalent resistance for the three resistors (3.2 ohms, 7.1 ohms, 5.8 ohms). I assumed they were in series and simply added them, and then added 1.0 ohms and 4.5 ohms to get the total resistance. I think this is wrong, can someone explain how you would go about calculating the Req?
 
Physics news on Phys.org
Sylvia said:

Homework Statement


screen_shot_2015-02-01_at_1.34.51_pm.png

Ignore the internal resistance of the battery and assume it is merely a battery. Calculate the equivalent resistance of the circuit.

Homework Equations


1/Req = 1/R + 1/R ... (parallel)
Req = R + R ... (series)

The Attempt at a Solution


I know this is fairly simple but I don't understand how you would calculate the equivalent resistance for the three resistors (3.2 ohms, 7.1 ohms, 5.8 ohms). I assumed they were in series and simply added them, and then added 1.0 ohms and 4.5 ohms to get the total resistance. I think this is wrong, can someone explain how you would go about calculating the Req?

I'm afraid you're wrong. All of them aren't in series. See the figure I've uploaded. What can you infer from that? Always deal with 2 resistances at a time. Don't involve 3 together.
 

Attachments

  • resistance.JPG
    resistance.JPG
    7 KB · Views: 621
I see what you are saying, since 7.1 and 5.8 are in series, they must be added together? And then added in parallel to 3.2?
 
Sylvia said:
I see what you are saying, since 7.1 and 5.8 are in series, they must be added together? And then added in parallel to 3.2?
You got that right mate!
 
thanks!
 
Sylvia said:
thanks![/QUOT
Glad I could help! :-)
 

Similar threads

  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 42 ·
2
Replies
42
Views
5K
Replies
5
Views
2K
Replies
9
Views
2K
Replies
6
Views
2K
  • · Replies 13 ·
Replies
13
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 6 ·
Replies
6
Views
3K