In metre-bridge experiment the balance point is obtained if the gaps are closed by $2 \Omega$ and $3 \Omega$. A shunt of $\mathrm{x} \Omega$ is added to $3 \Omega$ resistor to shift the balance point by 22.5 cm . The value of x is

In the following circuit, current through ACB if each resistance $\mathrm{R}=4 \Omega$ is

Kirchhoff's voltage law and current law are based (respectively) on the conservation of