Electric Field and Electric Field Lines

The governing concept is superposition of electric fields. For two positive charges, the fields between them point in opposite directions, so cancellation is possible there. If the charges are q and Q with Q greater than q, equality requires kq/x² = kQ/(d−x)². The point must be nearer q, because being closer increases the smaller charge's field until it balances the larger charge's field. Thus A is correct; the midpoint works only for equal charges.

Step 1: Moving slightly right makes the point closer to the right positive charge and farther from the left one. Step 2: The right charge repels the positive test charge leftward more strongly than the left charge repels it rightward. Step 3: Therefore the initial force is toward the left, so option A would be wrong if chosen.

Step 1: Electric field due to a point charge is directly proportional to charge and inversely proportional to the square of distance. Step 2: Tripling the charge makes the field three times and halving the distance makes it four times. Step 3: Combining both effects gives twelve times so handle both changes separately.

Step 1: At the midpoint the fields due to equal positive charges are equal and opposite. Step 2: Moving slightly right makes the point closer to the right charge so its leftward field becomes stronger. Step 3: Symmetry applies only at the exact midpoint so compare distances nearby.

Step 1: The field due to a negative charge points toward the charge. Step 2: Moving left from the midpoint makes the left charge closer so its leftward field is stronger than the rightward field. Step 3: The net field is toward the closer negative charge.

Step 1: Between opposite charges the fields point in the same direction so they do not cancel. Step 2: Outside the pair the directions can be opposite and near the smaller charge its field can balance the distant larger charge field. Step 3: For unequal opposite charges look outside for the zero point.

Step 1: The field of a point charge increases with charge magnitude and decreases with square of distance. Step 2: The smaller charge can balance the larger charge only when the point is closer to it. Step 3: For zero-field points, first check direction and then distance balance.

Step 1: Between opposite charges, the two fields point in the same direction, so cancellation is not possible there. Step 2: Outside the charges, the fields can be opposite. Step 3: The balance point lies outside on the side of the smaller charge because the larger charge must be farther away.