# In the experiment to find the value of unknown resistance using meter brige the circuit is as shown below . under the condition that the galavanometer shows null deflection value of R is :

$(a)\;100 \; \Omega \\(b)\;150 \; \Omega \\(c)\;200 \; \Omega \\(d)\;250\;\Omega$

Under null deflection in galvanometer
$\large\frac{R}{100-25}=\frac{50}{25}$
$\large\frac{R}{75}=\frac{50}{25}$
$R= 150\;\Omega$
Hence b is the correct answer.