In: Physics
A parallel-plate capacitor has 2.18 cm2 plates that are separated by 5.69 mm with air between them. If a 18.0 V battery is connected to this capacitor, how much energy does it store?
DATA:
SOLUTION
The energy stored by a parallel plate capacitor can be obtained using:
Where:
is the voltage on the capacitor.
is the capacitance, which is defined as:
Where:
is the permitivity of free space, which has a value of:
is the area of plates of the capacitor
is the distance between plates.
Now, first we need to find the capacitance , with the help of equation (2). Therefore, replacing (3) and data given values into equation (2) we have:
Solving we obtain:
Now, we can find the energy stored . Therefore, inserting (5) and data given values into equation (1) we have:
Solving we obtain: