Answer:
¹/₃₈₇ second
Explanation:
<em>The period of a wave is the reciprocal of its frequency.</em>
So, simply, the frequency is ¹/₃₈₇ second(s), as that is the reciprocal of the frequency, 387 Hz.
Answer:
The answer is D. density.
There are some missing information in the question.
However, since you are talking about magnetic force, I think you refer to the Lorentz force. When a particle of charge q and velocity v is immersed in a magnetic field of intensity B, the force acting on the particle is:

where

is the angle between the magnetic field and the direction of the particle.
Therefore, if force F is doubled, then also the velocity v must be double of its initial value:
See attachment file below.
Hope it helped!
Explanation:
The speed of light is 300,000,000 m/s. There are 8 zeros, so in scientific notation, the speed is 3×10⁸ m/s.