Posted by **fatih** on Thursday, February 16, 2012 at 9:51pm.

two unknown resistors a and b are connected together. when they are connected in series their combined resistance is 15 ohm. When they are connected in parallel, their combined resistance is 3.3 ohm. What are the resistances of A and B?

- physics -
**Henry**, Thursday, May 28, 2015 at 8:28pm
R1+R2 = 15 Ohms

R1*R2/(R1+R2) = 3.3 Ohms

In Eq2, replace R1+R2 with 15 Ohms:

R1*R2/(15) = 3.3

R1*R2 = 49.5

R1 = 49.5/R2

In Eq1, Replace R1 with 49.5/R2:

(49.5/R2)+R2 = 15

R2^2 + 49.5 = 15R2

R2^2 - 15R2 + 49.5 = 0

Use Quad. Formula:

R2 = 10.1 Ohms

R1 + 10.1 = 15

R1 = 4.9 Ohms

## Answer This Question

## Related Questions

- physics (please check) - A total resistance of 3 ohms is to be producd by ...
- Physics - Two resistors connected in series have an equivalent resistance of 783...
- physix - three resistances of value 1 ohm, 2 ohm and 3 ohm are connected in ...
- Physics - Thanks for any help :) Four 20 ohm resistors are connected in parallel...
- physics - the effective resistacce of two resistors connected in series is 100 ...
- Physics - What is the equivalent resistance of two resistors of 2 ohm and 3 ohm ...
- science - Three different resistors: 10 ohm, 20 ohm, and 20 ohm are connected in...
- science - Three different resistors: 10 ohm, 20 ohm, and 20 ohm are connected in...
- Chakote school solapur - if three resistors are connected in parallel there are...
- physics (please check) - Four 20-ohm resistors are connected in series and the ...

More Related Questions