Electric Field & Force

Front

What happens to the field strength as the distance between two charged objects decreases?

Back

The strength increases.

Answer explanation

The field strength between two charged objects is directly proportional to the product of their charges and inversely proportional to the square of the distance between them, according to Coulomb's Law. As the distance between the objects decreases, the field strength increases, making the correct choice 'the strength increases'.

Front

What happens to the field strength as the distance between two charged objects decreases?

Back

The strength increases.

Answer explanation

The field strength between two charged objects is directly proportional to the product of their charges and inversely proportional to the square of the distance between them, according to Coulomb's Law. As the distance between the objects decreases, the field strength increases, making the correct choice 'the strength increases'.

Front

A positive charge placed in an electric field experiences a force in the direction of the field.

Back

True

Answer explanation

A positive charge placed in an electric field indeed experiences a force in the direction of the field. This is because the electric field lines point from positive to negative charges, and a positive charge will naturally move along these lines, experiencing a force in the same direction as the field.

Front

Three equal point charges are placed at the corners of a square of side d as shown in Figure 19-9. Which of the arrows shown represents the direction of the net electric field at the center of the square?

Back

A

Answer explanation

The net electric field at the center of the square is the vector sum of the electric fields due to each point charge. Since the charges are equal, their electric fields at the center have equal magnitudes. The electric field due to the diagonal charges cancels out, leaving only the electric field due to the bottom-left charge, which points towards the top-right corner.

Front

Three equal point charges are placed at the corners of a square of side d as shown in Figure 19-9. What is the correct expression of the net electric field at the center of the square?

Back

Answer explanation

The net electric field at the center of the square can be found by calculating the electric field due to each charge and summing them up. Since the charges are equal and placed symmetrically, their electric fields will add up constructively. The correct expression for the net electric field is E = (k2q) / (d^2), as it takes into account the contributions from all three charges.

Front

Three equal point charges of varying signs are placed on the corners of a square of side d as shown in Figure 19-10. Which of the arrows shown represents the direction of the net electric field at the center of the square?

Back

A

Answer explanation

In the given question, three equal point charges are placed on the corners of a square. The net electric field at the center of the square will be the vector sum of the electric fields due to each charge. Since the charges have varying signs, the net electric field will be in the direction of the positive charge, which is represented by arrow A.

Front

Where can an electric field be found?

Back

in the space surrounding a charged object

Answer explanation

An electric field exists in the space surrounding a charged object. This field represents the force that a positive test charge would experience at any point in space due to the presence of the charged object. Therefore, the correct answer to the question is 'in the space surrounding a charged object'.

Front

Electrical field lines of a negatively charged object flow _______________.

Back

Inwards

Answer explanation

The electrical field lines of a negatively charged object flow inwards. This is because electric field lines always originate from positive charges and terminate at negative charges. In the case of a negatively charged object, the field lines would be entering the object, hence, they flow inwards.

Front

Which statement best describes the electric fields in the image?

Back

The field lines move away from a positive charge and toward a negative charge.

Answer explanation

The correct answer is that the field lines move away from a positive charge and toward a negative charge. This is because electric field lines always start from a positive charge and end at a negative charge, indicating the direction of the force that a positive test charge would experience.

Front

TRUE or FALSE: The electric field lines for a positive charge is always directed away from the charge.

Back

True

Answer explanation

True. The electric field lines for a positive charge are always directed away from the charge. This is because the direction of the electric field is defined as the direction in which a positive test charge would move if it was placed in the field. Therefore, the field lines for a positive charge radiate outwards, indicating that a positive test charge would move away from our positive charge.