Question

The current passing through the battery in the given circuit is:

Options

• 2.0 A

• 0.5 A

• 2.5 A

• 1.5 A

Answer 1

0.5 A

Explanation:

Since `2.5/5 = 1.5/3`, the bridge is balanced. This means no current flows through the 6 Ω resistor. 6 Ω across AD can be removed as V_A = A_D.

Branch 1 = 5 Ω + 3 Ω 

= 8 Ω

Branch 2 = 2.5 Ω + 1.5 Ω

= 4 Ω

R_BE = `(8 xx 4)/(8 + 4)`

= `32/12`

= `8/3` Ω

The circuit can be redrawn as:

The total resistance of the entire circuit includes the resistors in series with the battery:

`R_"total" = 5.5 + 1.5 + 1/3 + R_"BE"`

= `7 + 1/3 + 8/3`

 = `7 + 9/3`

= `(21 + 9)/3`

= `30/3`

= 10 Ω

Using Ohm’s law 

`I = V/R`

= `5/10`

= 0.5 A