Question

Show how would you join three resistors, each of resistance 9 Ω so
that the equivalent resistance of the combination is (i) 13Ω (ii) 6 Ω

Answer 1

(I)Equivalent resistance is 13 ohms

Two 9 ohm resistors are first connected in parallel

Rp=9/2=4.5

Now 4.5 ohm and 9 ohm are in series

Rs=4.5+9=13.5 ohm

(II) equivalent resistance is 6ohm

Two 9 ohm resistor are in series

Rs=9+9=18ohm

18 and 9 ohm are in parallel

Rp=18×9/18+9=162/27=6ohm

I hope this helps

Answer 2

Answer:(I)Equivalent resistance is 13 ohms

Two 9 ohm resistors are first connected in parallel

Rp=9/2=4.5

Now 4.5 ohm and 9 ohm are in series

Rs=4.5+9=13.5 ohm

(II) equivalent resistance is 6ohm

Two 9 ohm resistor are in series

Rs=9+9=18ohm

18 and 9 ohm are in parallel

Rp=18×9/18+9=162/27=6ohm

I hope this helps