Question

Kirchhoff’s law. Obtain the expression of balance condition of wheat-

stone Bridge.



This question is very IMPORTANT for class 12 board exam of year 2020-21 so give me correct answer use with pen ️ and paper otherwise I will report your answer..​

Answer 1

Hello, here is your answer.

Kirchhoff's circuit laws

• Kirchhoff's circuit laws are two equalities that deal with the current and potential difference in the lumped element model of electrical circuits. They were first described in 1845 by German physicist Gustav Kirchhoff. This generalized the work of Georg Ohm and preceded the work of James Clerk Maxwell.

Equation

• Kirchhoff's voltage law states that the algebraic sum of the potential differences in any loop must be equal to zero as: ΣV = 0. Since the two resistors, R1 and R2 are wired together in a series connection, they are both part of the same loop so the same current must flow through each resistor.

Kirchhoff’s law to obtain the expression of balance condition of wheat-stone Bridge.

We apply Kirchoff's current law in the shown circuit.

At junction B,

i1 = ig + i3

At junction D,

i2 + ig = i4

If current through the galvanometer is zero,

ig =0

thus i1 = i3

and i2 = i4

Applying Kirchoff's voltage law for loop ABDA,

i1 P + igG = i2R

Applying Kirchoff's voltage law for loop BCDB,

i3Q=i4S+igG

When ig =0,

i1P = i2r

and i3Q= i4S

But i1 =i3 and i2 = i4 ,

Therefore,

$\frac{p}{q} = \frac{r}{s}$

Answer 2

The bridge is in balance condition when no current flows through the coil or the potential difference across the galvanometer is zero. This condition occurs when the potential difference across the a to b and a to d are equal, and the potential differences across the b to c and c to d remain same...

Hope it's helpful for you... ☺️☺️