Question

Five resistors of different resistances are connected together as shown in the figure. A 12 V battery is connected to the arrangement. 

Calculate:
(i) the total resistance in the circuit
(ii) the total current flowing in the circuit.

Answer 1

(i) From given figure, R₁ and R₂ are parallel.

∵ `1/"R'" = 1/"R"_1 + 1/"R"_2`

`= 1/10 + 1/40 = 5/40 = 1/8`

∴ R' = 8 Ω

R₃, R₄ and R₅ are also parallel,

∴ `1/"R''" = 1/"R"_3 + 1/"R"_4 + 1/"R"_5`

`= 1/30 + 1/20 + 1/60 = 6/60 = 1/10`

∴ R'' = 10 Ω

∴ Total resistance in the circuit

= R'  R''

= 8 + 10 = 18 Ω

(ii) V = 12 volt.

∴ Total current flowing in the circuit ]

I = `"V"/"R" = 12/18`

`= 2/3 = 0.667` A.