Question

name and state the rule associated with electric motor

Answer 1

flemings right hand rule
if index finger and thumb and middle fingers are mutually perpendicular then
index=mag field
thumb=motion of coil
middle=direction of current

Answer 2

half-ring D comes in contact with brush A and half-ring C comes in contact with brush B. Hence, the direction of current in the coil MNST gets reversed. The current flows through the coil in the direction TSNM. ... The split rings help to reverse the direction of current in the circuit. These are called the commutator.
Working principle of a DC motor. A motor is an electrical machine which converts electrical energy into mechanical energy. The principle of working of a DC motor is that "whenever a current carrying conductor is placed in a magnetic field, it experiences a mechanical force".