Speed of violet light in vacuum

Explanation: Light travels at approximately 300,000 kilometers per second in a vacuum, which has a refractive index of 1.0, but it slows down to 225,000 kilometers per second in water (refractive index of 1.3; see Figure 2) and 200,000 kilometers per second in glass (refractive index of 1.5).

30 fN ( 30* 10^-15 N) and it is pointed to to -y-axis.

Explanation: In order tosolve this question we have to usethe Coulomb force given by:

F=e*E= 1.6 *10^-19 C* 1920 N/C= 30 fN the force pints in opossite direction of the electric field due to the sign of charge of the electron.