Question

A cylindrical capacitor is made of two thin-walled concentric cylinders. The inner cylinder has radius 8 mm , and the outer one a radius 11 mm . The common length of the cylinders is 152 m . What is the potential energy stored in this capacitor when a potential difference 8 V is applied between the inner and outer cylinder? (k =1/4∗π∗ϵ0=8.99×109N⋅m2/C2) A cylindrical capacitor is made of two thin-walled concentric cylinders. The inner cylinder has radius 8 , and the outer one a radius 11 . The common length of the cylinders is 152 . What is the potential energy stored in this capacitor when a potential difference 8 is applied between the inner and outer cylinder? ( =) 8.5×10−7 J 7.5×10−6 J 2.0×10−7 J 1.4×10−7 J 9.6×10−7 J

Answer 1

Answer:

So the answer is the first one

E = 8.5 x 10 ⁻⁷ J

Explanation:

Given:

r₁ = 8 mm , r₂ = 11 mm , h = 152 m

ε₀ = 8.85 x 10⁻¹² N * m² / C²

C = Q / V

C = 2π * h * ε₀ / ln ( r₂ / r₁ )

C = [ 2π * 152 m * 8.85 x 10⁻¹² N * m² / C² ]  / [ ln ( 11 mm / 8mm ) ]

C = 2.654 x 10⁻⁸ F

C = 26.54 nF

Now to determine the energy Emf

E = ¹/₂ * C * V²

E = ¹/₂ * 26.54 nF * 8²V

E = 8.5 x 10 ⁻⁷ J