The synchronous speed (Ns) of an induction motor can be calculated using the formula:

Ns = (120 * f) / p

where f is the frequency of the power supply, and p is the number of poles of the motor.

For the given motor with 4 poles and a power supply frequency of 50 Hz, the synchronous speed is:

Ns = (120 * 50) / 4 = 1500 rpm

The actual speed of the motor is 1300 rpm, which means that it is running at a speed slightly below the synchronous speed.

The difference between the synchronous speed and the actual speed is called slip (s). The slip can be calculated using the formula:

s = (Ns - N) / Ns

where N is the actual speed of the motor.

Substituting the values, we get:

s = (1500 - 1300) / 1500 = 0.133

The slip is 0.133 or 13.3%.

The speed of the stator magnetic field with respect to the rotor is given by:

Ns - N = 1500 - 1300 = 200 rpm