Physics
Physics
Problem
Show that, for two like charges and separated by a distance on a straight line, the point where the electric field vanishes lies on the line segment joining them and divides it internally in the ratio (measured from the larger charge ).Intuitive explanation
The electric field from each charge points away from it (since both are positive), so they can only cancel at a point between the charges where the weaker field from the farther charge balances the stronger field from the nearer one. Set up the condition that the magnitudes of the two fields are equal at some point, then solve for its position—you'll find that being closer to the larger charge is exactly what's needed for its field to match the smaller charge's field at that spot.
Intuitive explanation
The electric field from each charge points away from it (since both are positive), so they can only cancel at a point between the charges where the weaker field from the farther charge balances the stronger field from the nearer one. Set up the condition that the magnitudes of the two fields are equal at some point, then solve for its position—you'll find that being closer to the larger charge is exactly what's needed for its field to match the smaller charge's field at that spot.