Question

What is the nature of the force between balls A and C?

What is the nature of the force between balls A and C?

	strongly attractive
	strongly repulsive
	weakly attractive
	neither attractive nor repulsive

Answer 1

Concepts and reason

The concept required to solve the given problem is property of charges.

Initially, use the property of charge to determine the charge on the plastic balls A and C.

Then, using the property of induction and charges determine the nature of force between the plastic balls A and C.

Fundamentals

Electric charge: It is a property of matter that causes it to experience force when placed in electromagnetic field.

The properties of electric charge are:

1.Electric charge is quantized.

2.Conservation of charge: It states that an electric charge can neither be created nor destroyed.

3.Opposite charges attract each other and similar charges repel each other.

The two methods through which the transfer of charge between the two bodies takes place is given as:

(a)Charging by conduction

(b)Charging by induction

In the charging by conduction method, both the bodies acquire the same type of charge when both comes in contact with each other.

Consider a negatively charged metal sphere and a neutral object. When the sphere comes in contact with a neutral object, the excess number of electrons on the metal sphere moves towards the neutral object and evenly gets spread on the both the bodies. Due to this, the neutral object acquires negative charge while the metal sphere is still charged but has less number of electrons.

In case of positively charged metal plate and a neutral sphere, the electrons from the neutral sphere get attracted towards the positively charged metal plate and at the end the neutral sphere becomes positively charged.

This charging method occurred by contact is termed as “Charging by conduction”.

In the charging by induction method, when a charged object is brought near (not touch) to the neutral conducting object, charge gets induced on the object. In this process, the charged object is only used to induce charges (electron movement) on the neutral object. When the ground is touched to the sphere, the electron from the sphere moves towards the ground and the overall charge on the sphere becomes positive.

This charging method occurred without contact is termed as “Charging by induction”.

When the test charge is brought closer to the plastic ball A, it strongly attracts the test charge. Hence, the charge on the plastic ball A is negative.

Since the test charge gets weakly attracted to plastic ball C, thus the ball C is neutral in nature and hence due to the charging by induction, negative charge gets developed on the side of the plastic ball C where the test charge is brought close.

Thus, since the plastic ball A is negatively charged and the ball C is neutral, ball A will be weakly attracted to ball C. This is because when the plastic ball C will be brought closer to the plastic ball A the region of ball C closer to ball A will get positively charged and thus the ball A will get weakly attracted towards ball C.

Ans:

The nature of force between balls A and C will be weakly attractive.