Physics Chapter 16
Electrons in conducting materials are easily gained or lost, making it easier to conduct a charge.
Electrons in conducting materials are loosely held by atoms in contrast to electrons in insulators, which tend to be tightly held. How does this fact explain the difference between electrical conductors and electrical insulators?
insulated from Earth
A conductor, such as a copper rod, can be charged by contact with another charged object only if the metal rod is...
induction
A grounded conductor may be charged by the process of - .
no charge
A negatively charged rod is brought near a metal sphere that is not grounded. When the rod is taken away, the metal sphere will have --.
positive
A student rubs a certain rod with plastic wrap. The rod then repels a glass rod that has been rubbed with silk and attracts a rubber rod that has been rubbed with fur. This observation shows that the first rod has a(n) - charge.
r=1.39x10^-2 m
An electric field of 2250 N/C is produced by a charge of 4.82x 10^11 C. For this field strength, what is the distance to the charge? (kC=8.99x10^9 N•m^2/C^2).
4F
An electric force F exists between two objects separated from each other by distance r. If the distance is decreased to 0.5r, the force between the two objects becomes -- .
2F
An electric force F exists between two objects, both having the charge q. If the charge on one object is doubled to 2q, the force between the objects becomes -- .
vector
The resultant force acting on a charged object placed near other charged objects is the - sum of the of the individual forces acting on the object.
are field forces
Electric force and gravitational force are alike in that both forces ...
on the surface of the rod
In a charged conductor, such as an aluminum rod, the charge is...
electrons
Objects become electrically charged as a result of the transfer of -.
all charge is an integer multiple of a fundamental charge.
Robert Milliken's research showed that electric charge is quantized, which means that ...
negative
Rubbing a balloon through dry hair gives the balloon a - electric charge.
The charge can have any sign and any magnitude.
The diagram above represents an array of point charges of the magnitudes shown. Assume that no net force acts on charge q3. What can you say about the sign and magnitude of charge q3?
D
The diagram on the right represents a cross-section of a charged copper rod. Which of the arrows best represents a field line in the rod's electric field?
B
The diagram on the right represents a spherically shaped conductor with the protrusions shown. If this conductor is given an electrostatic charge, which letter best represents the location of the largest concentration of charge?
positive and larger in magnitude
The diagram on the right shows the electric field lines around two charges that have been brought near each other. From the diagram you can infer that the charge of the left is ... than the charge on the right.
The charge is negative as the field lines are curved towards the positive charge.
The drawing on the right is a partial diagram of an electric field showing only a few field lines (without arrowheads). The charge on the right is positive. Can the sign of the charge on the left be determined from the diagram? If so, what is the sign? Explain.
more lines per unit area
The electric fields of two charges, A and B, are represented by diagrams showing electric field lines. If charge B is greater than charge A, the diagram of charge B will have ... than the diagram of charge A.
a positive
The nucleus of an atom has -- electric charge.
the distance from the object.
The strength of an electric field around a charged object depends on both the magnitude of the charge and...
4
Two charged objects are near each other. One has a charge of 2.0x10^5 C and the other has a charge of 4.0x10^5 C. If the first charge doubles to 4.0x10^5 C, and the second charge doubles to 8.0x10^5 C, the force between the charges changes by a factor of - .
F=-499.4
Two point charges having charge values of 4.0x10^6 C and 8.0x10^6 C, respectively, are separated by 2.4x10^2 m. What is the value of the mutual force between them? (kC= 8.99x10^9 N•m^2/C^2)
1/16
Two point charges, initially 2 cm apart, are moved to a distance of 8 cm apart. By what factor does the resulting electric force between them change?
polarization
Uncharged objects can be attracted by a charged object because the uncharged objects acquire a surface charge by the process of - .
Electric force can both attract and repel.
Which of the following best represents a difference between electric force and gravitational force?
newtons per coulomb
Which of the following units is used to state the strength of an electric field?
a charged table tennis ball
Which of the following would be the best to use to determine whether an electric field is present around an object?