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

An electric motor operates on a $50\,V$ supply and a current of $12\,A$. If the efficiency of the motor is $30\%$,what is the resistance of the winding of the motor in $\Omega$?

The function of an electric motor is:

The back emf in a $DC$ motor is maximum when,

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: