Question

when two resistors are connected in series the effective resistance is 80 ohm when they are connected in parallel the effective resistance is 20 ohm what are values of two resistance?

Answer 1

In equation 1,

X+ y= 80

X= 80-y.

In equation 2,

1/x+ 1/y = 20

1/ 80-y+ 1/y =20

Y+ (80-y)/ y (80-y)= 1/20

y2+80-y /80y-y = 1/20

80/ 80 y- y2=1/20

80x20= 80y- y2

y2- 80 y + 1600 = 0

y2 -40y -40y +1600 = 0

y(y-40) -40(y-40) = 0

y= 40.

Thus, the values of two resistance are 40 ohm when two resistors are connected in series the effective resistance is 80 ohm when they are connected in parallel the effective resistance is 20 ohm.

Answer 2

Y = 40


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