Question

electrical capacity of spherical conductor of radius 9 km is
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Answer 1

Answer:

when it is connect to an earthed concentric thin hollow sphere of radius R ,the capacity becomes then the value R is

c=4π£0r

10c=4π£0=rR/R-r

10 =R/R-r

R=10/9

r=10/9×9

=10cm

Answer 2

Answer:

The answer to this question is 1MicroFarad.

Explanation:

To solve this question, first we need to know what exactly is electrical capacity.

Electrical capacity(also known as capacitance) is defined as the ability of a system to store charge. It is a function of the geometry of the design meaning it depends upon the area of the plates of the capacitor and the distance between them Also it depends upon the permittivity of the dielectric material between the plates of the capacitor.

Mathematically, it is defined as

C=q/V→ eq.(1)

where C is the electrical capacity or capacitance

q is the charge stored in the conductor and V is the electrical capacitance.

SOLUTION:

Now coming back to our given question.

Radius of the spherical conductor is given to be 9km. We need to find the electrical capacity.

We know that V for spherical conductor is same as that for the point charge which is V=q/(4$\pi$∈o*R)→eq. (2) where ∈o is the vacuum permittivity.

Substituting eq.2 in eq. 1 we get,

C=q/V⇒ q/(q/(4$\pi$∈o*R))

⇒ C=4$\pi$∈o*R

Substituting the value of 1/4$\pi$∈o=9*(10^9) N^2m^2 C^-2 and Radius = 9*10^3 m

⇒C=(9*10^3)/(9*10^9)

⇒C=10^-6 F

⇒C=1 Micro farad

Hence the answer is 1 Micro Farad.