Focuses light on the retina
A physical phenomenon produced by the motion of electric charge, resulting in attractive and repulsive forces between objects.
That is false. Hope this helped
To solve this problem we will apply the given relationship between wavelength, speed and frequency as well as the use of kinematic equations of motion description.
The wavelength is directly proportional to the speed and inversely proportional to the frequency, in other words,

Where
v = Velocity
f = Frequency
Speed is not given but if the distance traveled in a certain time, that is

Replacing



Substituting this value at our first equation we have



Therefore the wavelength of the seismic wave is 2000m
1b) the atom could lose its valence electron
c) protons are equal to electrons so there is no need to include it
d) the atom would need to gain electrons to fill its valence shell to become negative