A parallel plate capacitor with circular plates each has a diameter of 20 cm. Pl
ID: 1649496 • Letter: A
Question
A parallel plate capacitor with circular plates each has a diameter of 20 cm. Plates are separated by d = 2 mm and are charged by a battery of 60-V Find the capacitance of the capacitor What is the charge on the capacitor? What is the energy stored in the capacitor? If the air between the plates is replaced by a dielectric of K = 3 with the battery still connected. Find the capacitance of the capacitor. What is the charge on the capacitor? What is the energy stored in the capacitor? If the air between the plates is replaced by a dielectric of K = 3, but the disconnected first then the dielectric inserted. Find the capacitance of the capacitor.Explanation / Answer
Q2)
Capacitance of a Parallel plate capacitor is given by
C = (A/d) in Farads
is 8.854e-12 F/m
is dielectric constant (vacuum = 1)
A and d are area of plate in m² and separation in m
diameter = 20x10-2 m
radius = d/2=10x10-2 m
A = r² = (10x10-2)²
C = (A/d)=(8.854x10-12)((10x10-2)²) / (2x10-3)
=1.39x10-10 F
2)Charge on the capacitor is given by=Q=CxV=1.39x10-10 Fx60v
Q=8.34x10-9 =8.34 nC
3)energy stored in the capacitor can be written W=1/2 CV2
=.5x1.39x10-10 x 602= 2.50x10-6 Joules
B)
1)C = (A/d) in Farads
is 8.854e-12 F/m
is dielectric constant = 3
C = (A/d)=3x(8.854x10-12)((10x10-2)²) / (2x10-3)
=4.17 x10-10 F
2)
Charge on the capacitor is given by=Q=CxV=4.17 x10-10 Fx60v
Q=2.5x10-8 C
3)
energy stored in the capacitor can be written W=1/2 CV2
=.5x4.17x10-10 x 602 = 7.5x10-7 Joules