Question

in a wheatstone bridge p is equal to 100 ohm and, Q is equal 1000 ohm and r is equal to 40 ohm .if the galvanometer shows zero deflection determine the value of S

Answer 1

Explanation:

P/Q =S/R

100/1000=S/40

S= 40×10

S= 400

Answer 2

Answer:

The value of unknown resistance(S) is 400Ω .

Explanation:

A wheatstone bridge is said to be in balanced condition,when there is no current flowing through the circuit or potential difference across the galvanometer is zero.

In balanced condition,we can write that

                $\frac{P}{Q} = \frac{R}{S}$                                                [ S is unknown resistance ]

         or,  $S = R \times \frac{Q}{P}$  ........................................................(i)

Now, P = 100 Ω ,Q = 1000 Ω and R = 40 Ω

From equation (i),we will get

      $S = 40 \times \frac{1000}{100}$

           $= 400$ Ω

∴The value of unknown resistance(S) is 400Ω .