Which property of light remains unchanged when it enters a different medium?

Acar moves a distance of 50.0 km west, followed by a distance of 64.9 km north what was the magnitude of the displacement of the car, in units of kilometers?

Suppose a wire with a current is pushed upward by a magnetic field. how would the wire move if the direction of the current reversed? explain your answer.

An electron moves with a constant horizontal velocity of 3.0 × 106 m/s and no initial vertical velocity as it enters a deflector inside a tv tube. the electron strikes the screen after traveling 26 cm horizontally and 19 cm vertically upward with no horizontal acceleration. what is the constant vertical acceleration provided by the deflector? (the effects of gravity can be ignored.)