Electric field strength for a radial field - class-XII
Electric field behavior in radial configurations including conducting spheres, charged shells, and spherical charge distributions for Class XII physics
Questions
A charge is kept at the centre of a shell. Shell has charge Q uniformally distibuted over its surface and radius R. The force on the central charge due to the shell is :
- towards left
- towards right
- upward
- zero
A hollow conducting sphere of charge does not have electric field at
- outer point
- interior point
- beyond $2m$
- beyond $100m$
The rupture of air medium occurs at $E=3\times 10^6 \ V/m$. The maximum charge that can be given to a sphere of diameter $5 \ m$ will be (in coulomb):
- $2\times 10^{-2}$
- $2\times 10^{-3}$
- $2\times 10^{-4}$
- $2\times 10^{-5}$
A positive charge q is placed in a spherical cavity made in a positively charged sphere. The centres of sphere cavity are displaced by a small distance $\overrightarrow l $. Force on charge q is:
- in the direction parallel to vector $\overrightarrow l $
- in radial direction
- in a direction which depends on the magnitude of charge density in sphere
- direction can not be determined.
A thinwalled, spherical conducting shell S of radius R is given charge Q. The same amountof charge is also placed at its centre C. Which of the following statements are correct?
- On the outer surface of S, the charge density is $\displaystyle \frac {Q} {2 \pi R^2} $
- The electric field is zero at all points inside S
- At a point just outside S, the electric field is double the field at a point just inside S
- At any point inside S, the electric field is inversely proportional to the square of its distance from C
Two sphere's are isolated from each other. They each have an identical net positive charge and have the same radius, however, one sphere is solid and insulating, while the other is a hollow conducting sphere whose charge is uniformly distributed.
For which sphere is the electric field the greatest distance $x$ from the center of the spheres?
Assume $x$ is less than the radius of the spheres.
- The conducting hollow sphere has a greater E-field.
- The insulating solid sphere has a greater E field.
- Both spheres have the same E field.
- Neither sphere would cause there to be an Electric field.
As one penetrates through uniformly charged conducting sphere, what happens to the electric field strength:
- decreases inversely as the square of the distance
- decreases inversely as the distance
- becomes zero
- increases inversely as the square of distance
The magnitude of the electric field on the surface of a sphere of radius $r$ having a uniform surface charge density $\sigma$ is
- $\sigma / \epsilon _{0}$
- $\sigma / 2\epsilon _{0}$
- $\sigma / \epsilon _{0}r$
- $\sigma / 2\epsilon _{0}r$
Consider a thin spherical shell of radius $R$ consisting of uniform surface charge density $\sigma$. The electric field at a point of distance $x$ from its centre and outside the shell is
- inversely proportional to $\sigma$
- directly proportional to ${x}^{2}$
- directly proportional to $R$
- inversely proportional to ${x}^{2}$
Two charged spheres having radii a and b are joined with a wire then the ratio of electric field $\dfrac{E _a}{E _b}$ on their surface is?
- a/b
- b/a
- ba
- None of these
Charges $Q _1$ and $Q _2$ are placed inside and outside respectively of an uncharged conducting shell. Their seperation is r.
- The force on $Q _1$ is zero.
- The force on $Q _1$ is $\displaystyle k \frac{Q _1 Q _2}{r^2}$
- The force on $Q _2$ is $\displaystyle k \frac{Q _1 Q _2}{r^2}$
- The force on $Q _2$ is zero.