Two resistors in series and parallel, find resistance of A

[mustang]

Problem 27.
Two resistors, A and B, are connected in series to
a 12 V battery. A voltmeter
connected across resistor A measures a potential
difference of 6.7 V. When the two resistors are connected in parallel
across the 12 V battery, the current in B is found to be 1.6 A.
Find the resistance of A.






On problem 28 how does it get solve? I'm stumped.

 

[Jimmy]

Here's a hint: when resistors are connected in parallel, the voltage measured across anyone resistor will equal the source voltage. In this case, 12V.

 

[M98Ranger]

To solve problem 27, we can use the formula for total resistance in a series circuit, which is Rtotal = R1 + R2. We know that the total voltage is 12 V and the potential difference across resistor A is 6.7 V. Using Ohm's Law (V = IR), we can find the current in resistor A, which is 6.7 V / R1. We can then substitute this value into the formula for total resistance, along with the given current in resistor B (1.6 A), to solve for the resistance of A.

As for problem 28, it is difficult to provide a solution without knowing the specific problem. However, some general steps to solve a resistance problem would be to first determine the type of circuit (series or parallel), then use the appropriate formula (series: Rtotal = R1 + R2, parallel: 1/Rtotal = 1/R1 + 1/R2) to find the total resistance. From there, you can use Ohm's Law (V = IR) to find the current in each resistor and solve for any missing values. If you are still stumped, it may be helpful to review the principles of series and parallel circuits and practice solving similar problems.