Question

two resistances connected in parallel have effective resistance 20 ohm. if their ratio is 1 : 4, find the value of each resistor.

Answer 1

HOLA !!!

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HERE IS YOUR ANSWER

GIVEN

□ r1,r2 are in parallel.

□Their effective resistance (Rp) = 20ohms

□Their ratio = 1:4

r1 = ?

r2=?

SOLUTION

Let the resistance od the resistors r1, r2 be 1x and 4x respectively.

We know Rp = (r1 × r2) / (r1+r2)

(When two resistors are connected in parallel)

Substitute values:

20 = (1x × 4x)/ (1x+4x)

20 = 4x^2/ 5x

20 = 4x/5

4x = 20×5

4x = 100

x = 100/4 = 25 ohms

therefore r1 = 1x = 1 (25) = 25 ohms

r2 = 4x = 4 (25) = 100 ohms

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