1.
Field lines start on positive charges and end on negative charges.
Correct Answer
A. True
Explanation
Field lines represent the direction of the electric field. Electric field lines always start on positive charges and end on negative charges. This is because positive charges repel each other, so the electric field lines originating from positive charges move away from each other. On the other hand, negative charges attract positive charges, so the electric field lines converge towards negative charges. Therefore, it is true that field lines start on positive charges and end on negative charges.
2.
When drawing field lines, the lines should always cross.
Correct Answer
B. False
Explanation
Field lines should not always cross. In fact, field lines should never cross each other. Field lines represent the direction and strength of a field, such as an electric or magnetic field. If field lines were to cross, it would imply that the field has two different directions or strengths at the same point, which is not possible. Therefore, the correct answer is False.
3.
Electric field lines are used to describe the electric field around a charged object.
Correct Answer
A. True
Explanation
Electric field lines are a visual representation used to describe the direction and strength of the electric field around a charged object. They provide a way to visualize the electric field and understand its behavior. The lines always point away from positive charges and towards negative charges, and the density of the lines indicates the strength of the electric field. Therefore, it is true that electric field lines are used to describe the electric field around a charged object.
4.
When two equally charged plates are placed over one another, the field lines between them are completely straight and not evenly spaced.
Correct Answer
B. False
Explanation
When two equally charged plates are placed over one another, the field lines between them are evenly spaced and not completely straight. This is because the electric field between the plates is uniform, causing the field lines to be evenly spaced. Additionally, the field lines are curved due to the presence of the electric field. Therefore, the correct answer is false.
5.
Some organisms produce electric fields.
Correct Answer
A. True
Explanation
Some organisms, such as electric eels and certain types of fish, have the ability to produce electric fields. They do this through specialized organs called electrocytes, which generate electrical currents. These electric fields are used for various purposes, such as hunting, communication, and navigation. Therefore, it is true that some organisms can produce electric fields.
6.
In electrostatic representations electric field lines start on ________ charges and end on _______ charges.
Correct Answer
positive and negative, postive negative, positive, negative
Explanation
In electrostatic representations, electric field lines start on positive charges and end on negative charges. This is because electric field lines represent the direction of the force experienced by a positive test charge placed in the field. Positive charges repel positive test charges, so the field lines start from positive charges. On the other hand, negative charges attract positive test charges, so the field lines end on negative charges. Therefore, the correct answer is positive and negative.
7.
The electric field is _____ at the midpoint of two equally charged particles.
Correct Answer
zero
Explanation
The electric field is zero at the midpoint of two equally charged particles because the electric fields created by the two particles cancel each other out. Since the particles have equal charges, the magnitudes of their electric fields are equal but opposite in direction. Therefore, at the midpoint, the electric fields add up to zero, resulting in a net electric field of zero.
8.
The magnitude of the electric field between two equally charged plates is directly ___________ to the charge per unit.
Correct Answer
Proportional
Explanation
The magnitude of the electric field between two equally charged plates is directly proportional to the charge per unit. This means that as the charge per unit increases, the electric field also increases in magnitude. Similarly, if the charge per unit decreases, the electric field will also decrease in magnitude. The relationship between the two variables is such that any change in one will result in a corresponding change in the other, maintaining a proportional relationship.
9.
When a test charge is placed between two equally charged plates the charge is _______ by the upper plate and _________ to the lower plate.
Correct Answer
repelled, attracted
Explanation
When a test charge is placed between two equally charged plates, it experiences a force due to the electric field created by the plates. Since the plates have the same charge, the electric field between them is uniform. The test charge, being of the same polarity as the plates, is repelled by the upper plate. At the same time, it is attracted to the lower plate due to the opposite charges. Therefore, the charge is repelled by the upper plate and attracted to the lower plate.
10.
The number of lines leaving a positive charge or approaching a negative charge is proportional to the _________ of the charge.
Correct Answer
magnitude
Explanation
The number of lines leaving a positive charge or approaching a negative charge is proportional to the magnitude of the charge. This means that the greater the magnitude of the charge, the more lines will be leaving or approaching it. This is because the electric field lines represent the strength and direction of the electric field, and the magnitude of the charge determines the strength of the electric field it creates. So, a larger charge will have a stronger electric field and therefore more electric field lines.