Formula for Electric Field strength , E = V/d
where V = Voltage in volts, and d = distance of separation in meters.
d = 0.5 cm = 0.005 m, V = 12 V
E = V/d = 12 / 0.005
E = 2400
Electric Field Strength = 2400 Volts/meter
Your answer is cumulonimbus clouds
The frequency of a simple harmonic oscillator such as a spring-mass system is given by

where
k is the spring constant
m is the mass attached to the spring.
Re-arranging the formula, we get:

and since we know the constant of the spring:

and the frequency of oscillation:
f=1.00 Hz
we can find the value of the mass attached to it:
A=(vf-vi)/t
a=(50-25)/10
a=2.5m/s^2
Can you give more information