As we know that two charges exert force on each other when they are placed near to each other
The force between two charges is given as
here we know that
= two different point charges
r = distance between two point charges
also we know that two similar charges always repel each other while two opposite charges always attract each other
so here correct answer would be
<em>A. A positive and negative charge attract each other.</em>
An ideal air-filled parallel plate capacitor with plate a separation of 4.0 cm has a plate area of 0.040 m2. what is the capacitance of this capacitor with air between these plates<u> 8.9 pF.</u>
An ideal air-filled parallel-plate capacitor has round plates and carries a fixed amount of equal but opposite charge on its plates.
The capacitance of a parallel plate capacitor depends on area of each plate, dielectric medium between the plates and distance between the plates.
The amount of energy stored in a plate capacitor is given by
⇒ U = ,
where, Q is the stored charge and C is the capacitance,
To learn more about parallel plate capacitor, here
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