Mid way between the two equal and similar charges, we placed the third equal and similar charge. Which of the following statements is correct, concerned to the equilibrium along the line joining the charges ?a)The third charge experienced a net force inclined to the line joining the chargesb)The third charge is in stable equilibriumc)The third charge is in unstable equilibriumd)The third charge experiences a net force perpendicular to the line joining the chargesCorrect answer is option 'B'. Can you explain this answer?

Question

Answer

The charge in the middle experiences force along the line. The equilibrium is stable along the line connecting charges while The equilibrium is unstable along the line perpendicular to the line of charges
∴ Only option B is correct (given consider equilibrium only along line joining charges).

Answer

Explanation:
When two equal and similar charges are placed at some distance from each other, then the electric field is produced along the line joining the charges. On the other hand, if a third charge is placed on this line, then it experiences a force due to the electric field produced by the other two charges.

Types of Equilibrium:
1. Stable equilibrium: A body is said to be in stable equilibrium if the body, after being slightly displaced from its original position, tends to come back to its original position. In this case, the net force acting on the body is zero and the potential energy of the body is minimum.

2. Unstable equilibrium: A body is said to be in unstable equilibrium if the body, after being slightly displaced from its original position, tends to move away from its original position. In this case, the net force acting on the body is zero and the potential energy of the body is maximum.

3. Neutral equilibrium: A body is said to be in neutral equilibrium if the body, after being slightly displaced from its original position, remains in its new position. In this case, the net force acting on the body is zero and the potential energy of the body remains the same.

Answer:
In the given situation, the third charge is placed midway between the two equal and similar charges. Therefore, the charge experiences forces due to the electric fields produced by the other two charges.

As the two charges are equal and similar, the electric field produced by them is along the line joining the charges. Hence, the third charge experiences a net force along the line joining the two charges.

Since the third charge is placed midway between the two charges, the forces acting on it are equal and opposite in direction. Therefore, the net force acting on the third charge is zero, and as a result, it is in equilibrium.

Moreover, if the third charge is slightly displaced from its original position, it tends to come back to its original position. Therefore, the third charge is in stable equilibrium.

Answer

The repulsive forces on the 3rd charge due to 1st and the 2nd charges are equal in magnitude and are directed in the opposite direction to each other. Hence, the effect of these forces on the 3rd charge cancels out and it remains in stable equilibrium.

Similar Class 12 Doubts

Two positive and equal charges are fixed at a certain distance. A third small charge is placed in between the two charges and it experiences zero net force due to the other two.

Two positive and equal charges are fixed at a certaindistance. A third small charge is placed in between thetwo charges and it experiences zero net force due tothe other two.

A consumer consumes only two goods. For the consumer to be in equlilibrium , why must MRS between the two goods must be equal to the ratio of prices of these two goods ? is it enough to ensure equilibrium?

Why is the equality between marginal cost and marginal revenue necessary for the firm to be in equilibrium? Is it sufficient to ensure equilibrium? Explain with diagram and schedule.?

Top Courses for Class 12

Suggested Free Tests

Related Content

Schools

Competitive Examinations

Quick Access Links

Technical Exams