Question

The current I₃ in the following circuit is ____________.

Options

• `(-2)/35  "A"`

• `4/35  "A"`

• `2/35  "A"`

• `(-4)/35  "A"`

Answer 1

`(-4)/35  "A"`

Explanation:

Considering direction of I₁ and I_2,

I₁ + I₂ = I₃

Applying Kirchhoff's voltage law in loop BCDEB,

25I₃ + 5 + 50I₂ = 0

25I₃ + 5 + 50(I₁ + I₃) = 0

∴ 50I₁ + 75I₃ = -5        .... (i)

Applying Kirchhoff's voltage law in loop ABCDEFA,

- 100I₁ + 25I₃ = - 10      .... (ii)

From equation (i) and (ii),

175I₃  = -20

`"I"_3 = (-4)/35  "A"`