Here's a useful factoid that you don't hear about very often:
1 volt means 1 Joule per Coulomb.
When 1 coulomb of charge falls or gets lifted through 1 volt potential difference, it gains or loses 1 Joule of energy.
If you want to lift 5 coulombs to a height of 1 volt, you have to give it 5 joules.
If you actually give those 5 coulombs 7.5 joules instead, they'll rise up to 1.5 volts above the potential where they started. The flowed through a potential DIFFERENCE of 1.5 volts.
(If they started at a point that's connected to the Earth, like a water pipe or a metal flagpole, then their new potential is 1.5 volts, because we define zero as the potential of the ground.)
According to the conservation of mechanical energy, the kinetic energy just before the ball strikes the ground is equal to the potential energy just before it fell.
Therefore, we can say KE = PE
We know that PE = m·g·h
Which means KE = m·g·h
We can solve for h:
h = KE / m·g
= 20 / (0.15 · 9.8)
= 13.6m
The correct answer is: the ball has fallen from a height of 13.6m.
Answer:
L = 22.97 H
Explanation:
Given that,
Capacitance, 
Oscillation frequency, f = 0.5 Hz
The frequency of an AC circuit is given by :

Where
L is impedance

So, the impedance of LC circuit 22.97 H.