The inductive-inertial phenomenon is the precondition of the E/M waves, while the spin oscillations of the electron cause the E/M formations. The photon is the autonomous motion of the E/M wave with constant photon length and the number of its fundamental E/M waves determines its wavelength. The light speed is determined as the transmission speed of the disturbance into the tense elastic-dynamic space. However, the light speed depends on the cohesive pressure that is proportional to the square of the distance from the Universe center and therefore it is a local constant in our region. The change of cohesive pressure in electric fields directly affects the change in the light speed, which can be attributed to photon refraction phenomena. The deviation of E/M waves in the dynamic fields occurs, of course, in the gravitational field as well. It is proved, the light has gravity only in the back half-space with result the gravitational redshift of the stars spectrum, while gravitational blueshift cannot be detected, since there is no gravity in the front half-space of the E/M wave.