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 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 $,A$)

$A$ rectangular coil of a simple $A.C.$ generator rotates about one of its diameters with a constant angular frequency in the presence of a uniform magnetic field. The direction of the induced current reverses for the third time after how many rotations of the coil?

$A$ device which converts electrical energy into mechanical energy is

In a $dc$ motor, induced $e.m.f.$ will be maximum:

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