Question

In following figure, a current of 1.4 A flows towards the bridge circuit. The current in 2 n resistor is ______.

Options

• 1.4 A

• 1.2 A

• 1.0 A

• 0.6 A

Answer 1

In following figure, a current of 1.4 A flows towards the bridge circuit. The current in 2 n resistor is 1.0 A.

Explanation:

The bridge is balanced because

`"P"/"Q" = "R"/"S" (because (10  Omega)/ (2  Omega) = (25  Omega)/(5  Omega))`

Hence, there will be no current, through the 10 `Omega` resistance and galvanometer. Let the current through arm ABC be I. Then current through the arm ADC will be ( 1.4 - I). Hence,

(10 + 2) I = (25+ 5) (1.4 - I)

`therefore 12  "I" = 30 xx 1.4 - 30  "I"`

`therefore 42  "I" = 30 xx 1.4 - 30  "I"`

`therefore "I" = (30 xx 1.4)/42 = 1  "A"`