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Question
Consider a region inside which there are various types of charges but the total charge is zero. At points outside the region
- the electric field is necessarily zero.
- the electric field is due to the dipole moment of the charge distribution only.
- the dominant electric field is `∞ 1/r^3`, for large r, where r is the distance from a origin in this region.
- the work done to move a charged particle along a closed path, away from the region, will be zero.
Options
b and d
a and c
b and d
c and d
Solution
c and d
Explanation:
From Gauss’ law, we know `oint_s` E.dS = `q_(enclosed)/ε_0` in left side equation.
The electric field is due to all the charges present both inside as well as outside the Gaussian surface. Hence if `q_(enclosed)` = 0, it cannot be said that the electric field is necessarily zero.
If there are various types of charges in a region and total charge is zero, the region may be supposed to contain a number of electric dipoles.
Therefore, at points outside the region (maybe anywhere w.r.t. electric dipoles), the dominant electric field `∞ 1/r^3` for large r.
The electric field is conservative, work done to move a charged particle along a closed path, away from the region will be zero.
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