JEE Advanced2011PhysicsElectrostaticsActual
Which of the following statement(s) is/are correct?
Options
- AIf the electric field due to a point charge varies as r^ -2.5 instead of r⁻² , then the Gauss's law will still
- BThe Gauss's law can be used to calculate the field distribution around an electric dipole
- CIf the electric field between two point charges is zero somewhere, then the sign of the two charges is the sam
- DThe work done by the external force in moving a unit positive charge from point A at potential V_A to point B
Correct answer
C. If the electric field between two point charges is zero somewhere, then the sign of the two charges is the sam
Step-by-step solution
If charges are of opposite signs, then the two fields are along the same direction. So, they cannot be zero. Hence, the charges should be of same sign. Therefore, option (c) is correct. Further, work done by external force = change in potential energy aligned & W_ A B =q( V) & =(+1) (V_B-V_A ) & or W_ A B =V_B-V_A & aligned Therefore, option (d) is also correct. Correct options are (c) and (d). Analysis of Question (i) Question is simple. (ii) W= U (by external force) If charge is just moved, without changing the k