A capacitor is formed from two concentric spherical conducting shells separated by vacuum. The inner sphere has radius 11.5cm , and the outer sphere has radius 16.5cm . A potential difference of 100V is applied to the capacitor.

What is the energy density at r= 11.6cm , just outside the inner sphere?

What is the energy density at r = 16.4cm , just inside the outer sphere?

Explanation:

radius of inner sphere, a = 11.5 cm = 0.115 m

radius of outer sphere, b = 16.5 cm = 0.165 m

Voltage, V = 100 V

the capacitance of the spherical capacitor is given by

C = 4.22 x 10^-11 F

Charge, Q = c x V

Q = 4.22 x 10^-11 x 100

Q = 4.22 x 10^-9 C

(a) r = 11.6 cm = 0.116 m

The electric field at a distance r is given by

Where, K is the Coulombic constant

E = 2820.3 N/C

The energy density is given by

u = 3.52 x 10^-5 J/m³

(b) r = 16.4 cm = 0.164 m

The electric field at a distance r is given by

Where, K is the Coulombic constant

E = 1412.1 N/C

The energy density is given by

u = 8.83 x 10^-6 J/m³

r=rho l/a where a is the area, l is the length and rho is resistivity so the greater the area the lesser the resistance thats why the earth pin is thicker bcos current follow the shortest path, so less resistive .

the independent variable, the one that is intentionally manipulated, is whether or not the car hits the barrier.

the dependent variable, the one that you measure the response in, is the distance that the washers travel.