A battery of emf 10V is connected to a uniform wire AB of 1m length and having a resistance of  $10\Omega$  in series with a  $10\Omega$  resistor as shown in the figure. Two cells of emf 2V and 3V having internal resistances  $2\Omega$  and $3\Omega$  respectively are connected as shown in the figure. If the galvanometer shows null deflection at point J on the wire, the distance of point J from the point B is _____