00:02
Hi, in the given problem we have been given a solid metallic charged sphere like this.
00:20
Suppose it is having a total charge distributed everywhere within it, that is q, capital q.
00:55
Its radius is given as capital r and in the first part of the problem we have to find electric field at a point whose distance is smaller where this r is either equal to or greater than this capital r so suppose this observation point is here this is p at a distance small r so the gaussian surface passing through this observation point is in the form of a shell.
01:36
Now the charge, the total charge included within this gaussian surface is capital q plus suppose the observation point is p at a distance smaller hence the gaussian surface is in the form of a shell spherical shell of radius smaller hence using theorem which says the total electric flux linked with the gaussian surface that is equal to surface integral of electric field first of all and then also it is given as 1 upon epsilon times the total charge and closed by 8 now as the electric field lines are linked through this gaussian surface perpendicularly everywhere they are perpendicular.
03:10
So we can say the angle between area vector and electric field is 0 degree.
03:20
So here it will come out to be eds, cos 0 degree which later will become 1 is equal to 1 1 upon epsilon 0 times the charge and closed.
03:33
Electric field will be constant everywhere because it is at the same distance from the center of the solid sphere.
03:39
So that will come out to be constant remaining, leaving behind integration of ds only is equal to 1 upon epsilon not times the charge and closed.
03:50
So this ds means the area, surface area of the gaussian surface which is 4 pi r square is equal to 1 upon epsilon note times the charge and close.
04:00
So finally this electric field here will come out to be 1 upon 4 pi epsilon 0 into q by r square.
04:10
So it says electric field outside the sphere, the solid sphere, will be depending on the square of the distance inversely, which will be used in order to draw, in order to plot the curve for the electric field with the distance.
04:30
Now, in the second part of the problem, we have to find the same electric field but this time at a point which is within this solid sphere...