Question

A sphere of radius $1cm$ has potential of $8000V$, then energy density near its surface will be

• A. $64 \times 10^{5}J/m^{3}$
• B. $8 \times 10^{3}J/m^{3}$
• C. $32J/m^{3}$
• D. $2.83J/m^{3}$

Answer 1

Answer: (D)

$2.83J/m^{3}$

Answer 2

Energy density

$u_{e} = \frac{1}{2}\varepsilon_{0}E^{2} = \frac{1}{2} \times 8.86 \times 10^{- 12} \times \left( \frac{V}{r} \right)^{2}$= 2.83 J/m³