Christmas lights that stay on when one bulb burns out are wired as parallel circuits. Resistors can be used with parallel electrical circuits to restrict the current flow and produce heat.

Question

If the first resistor (R1) = 20 Ohms, the second resistor (R2) = 30 Ohms and the Equivalent Resistance (REQ) is 20/3 use the formula below to find the value of R3.

1/(R_eq) = 1/(R1)+ 1/(R2)+ 1/(R3)

What unit should I use for my answer?

To find the answer I …….

Answer 1

so, plug in the numbers:

1/(20/3) = 1/20 + 1/30 + 1/R3
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