The armature of a $DC$ motor has $20\,\Omega$ resistance. It draws a current of $1.5\,A$ when run by a $220\,V$ $DC$ supply. The value of the back $EMF$ induced in it will be......$V$

$A$ motor starter:

$A$ motor having an armature of resistance $2\,\Omega$ is designed to operate at $220\,V$ mains. At full speed,it develops a back $e.m.f.$ of $210\,V$. When the motor is running at full speed,the current in the armature is: (in $,A$)

An $AC$ generator consists of a coil of $500$ turns and area $2\ m^2$ rotating at an angular speed of $30\ rad\ s^{-1}$ in a uniform magnetic field $B = 0.20\ T$ between two fixed pole pieces. The resistance of the circuit including that of the coil is $1000\ \Omega$. What is the maximum current drawn from the generator?

Armature current in a $DC$ motor will be maximum when:

The output of a dynamo using a split-ring commutator is