The effective resistance between $A$ and $B$ is ........... $\Omega$.

The current from the battery in the given circuit is ................ $A$.

The value of current through the $20\,\Omega$ resistor is .................. $A$.

The given figure shows a network of resistances and two batteries. Which of the two batteries is getting charged?

The charge accumulated on the capacitor connected in the following circuit is . . . . . . $\mu C$ (Given $C=150\ \mu F$)

$A$ Wheatstone's bridge is balanced with a resistance of $625\, \Omega$ in the third arm,where $P, Q$ and $S$ are in the $1^{st}, 2^{nd}$ and $4^{th}$ arm respectively. If $P$ and $Q$ are interchanged,the resistance in the third arm has to be increased by $51\,\Omega$ to secure balance. The unknown resistance in the fourth arm is ............. $\Omega$.