Question

A charged body has an electric flux F associated with it. Now if the body is place inside a conducting shell then the electric flux outside the shell is:
A) zero
B) greater than F
C) less than F
D) equal to F

Answer 1

Electric flux is defined as the flow of electric field through a given area on the surface. There are two types of electric flux uniform and non-uniform. The electric flux is proportional to the number of lines passing through the area.
Formula used: The formula of the Gauss’s law is $\phi = \dfrac{Q}{{{\varepsilon _o}}}$ where $\phi$ is the electric flux and Q is the enclosed charge and ${\varepsilon _o}$ is the permittivity.

Step by step solution:
It is given that a charged particle is placed inside the conducting shell. In this case the electric flux that will leave the conducting shell will be zero because of the electrostatic shielding of the conducting shell.
The electric flux given for this case is equal to zero.

The correct answer for this problem is option A.

Additional information: The concept of shielding is very important in the real world as at the time of thunderstorms it is advised to get cover inside the car and not stand in open or under the tree due to shielding so we can save our lives. The fuel in the rocket is conserved by providing shielding only. Another formula of Gauss’s law is given by $\oint {\vec E \cdot d\vec S} = \dfrac{q}{{{\varepsilon _o}}}$ where $\vec E$ is the electric field $\vec S$ is the surface area q is the charge and ${\varepsilon _o}$ is the permittivity of the air.

Note: It is advisable to the students to remember and understand Gauss's law as it can help in solving these types of problems. Also sometimes numerical problems can be asked based on Gauss's law. The electric flux is always perpendicular to the surface area of the body.