TEST ON DEC 3
A circuit is built based on the circuit diagram shown. What is the current in the 50 Ω resistor?
1.2 A
A series circuit contains a 30 Ω resistor, a 20 Ω resistor, and a 10 Ω resistor. The power supply provides 100 V to the circuit. The current in the 10 Ω resistor, to two significant figures, is
1.7 A
A 7.2 × 10-5 C charge has an electric potential energy of 1.08 × 10-2 J. The electric potential, to the nearest whole number, is
150 V
A ceiling fan draws a current of 0.625 A and has a voltage of 120 V. The resistance of the ceiling fan, to the nearest whole number, is
192
A power source that provides a current of 1.6 A to two 5 Ω resistors connected in series is moved to a parallel circuit that consists of three identical resistors. In the parallel circuit, the overall current is 2.0 A. The value of a resistor used in the parallel circuit is
24
A wire delivers 12.0 C of charge in 4.0 s. What is the current in the wire?
3.0 A
What is the electric potential energy of a charge that experiences a force of 3.6 × 10-4 N when it is 9.8 × 10-5 m from the source of the electric field?
3.5 × 10-8 J
In 12 s, a wire delivers 96 C of charge. The current in the wire, to the nearest whole number, is
8 A
Which statement correctly describes the formation of an electric current?
A voltage causes electric charges to move from higher to lower potential.
Which statements best characterize conductors? Check all that apply.
Conductors allow electricity to easily move through them. metal is an example of a conductor
Which equation relates charge, time, and current?
I=triangleq/t
How does the electrical force relate to the charge of an object?
It is directly proportional to the charge.
One charge is decreased to one-third of its original value, and a second charge is decreased to one-half of its original value. How will the electrical force between the charges compare with the original force?
It will decrease to one-sixth the original force.
Jason makes a graphic organizer for insulators and conductors and wants to add the following labels to it. Label 1: Lacks free electrons Label 2: Aluminum In which regions should Jason place each label?
Label 1: X Label 2: Z
For a constant voltage, how is the resistance related to the current?
Resistance is inversely proportional to current, so when the resistance doubles, the current is cut in half.
A negative test charge experiences a force to the right as a result of an electric field. Which is the best conclusion to draw based on this description?
The electric field points to the left because the force on a negative charge is opposite to the direction of the field.
Which statements correctly compare the gravitational force with the electrical force? Check all that apply.
The gravitational force can be attractive. The electrical force can be repulsive. The electrical force can be attractive. Any two objects experience a gravitational force between them
How do the charges compare when two objects are charged through friction?
The objects become oppositely charged and have equal amounts of charge.
Three charges are located at the vertices of a triangle, as shown. Which vector best represents the net force acting on the +4 C charge in the diagram?
X
After hearing about an accident on his normal route, Mr. Gujral checks for alternate routes to get to work. What type of circuit does this traffic situation model?
a parallel circuit because there is more than one path
Through which element would someone most likely receive a shock?
chromium (Cr)
What can a transistor do in order to fulfill its function in a circuit? Check all that apply.
control its own semiconductance act like an insulator act like a conductor
Which quantities are equal to total of the individual values within a circuit?
the current in a parallel circuit and the voltage in a series circuit
Which pair does NOT have an electric force between them?
two neutral objects
What is the direction of the electric field at a point directly below a negative charge, Q?
up
Current 1 of 8.4 A runs for 240 seconds and then stops. Current 2 is 10.5 A. How long does current 2 have to run to deliver the same amount of charge as current 1?
192 s
The magnitude of the electrical force acting between a +2.4 × 10-8 C charge and a +1.8 × 10-6 C charge that are separated by 0.008 m is_____rounded to the tenths place.
6.1 N
Which are disadvantages of series circuits? Check all that apply.
A break in one wire causes all current to stop. If one bulb goes out, the others go out.
Humberto builds two circuits using identical components. Circuit 1: A series circuit with three lightbulbsCircuit 2: A parallel circuit with three lightbulbs He then adds two more lightbulbs in a series with the bulbs in circuit 1 and two more lightbulbs on new branches in parallel with each bulb in circuit 2. What can he expect to see?
All bulbs in circuit 1 will shine more dimly than the original bulbs, while all bulbs in circuit 2 will have the same brightness as the original bulbs.
Roland writes a story in which boaters become stranded on a sandy island. In the story, they set about collecting materials to create semiconductors to repair computer components in their radio. Which problem is likely to be the most difficult for Roland's characters to overcome?
Any substances they find are too impure.
How does the electrical force relate to the distance between two charged objects?
It is inversely proportional to the square of the distance.
How does a rubber rod become negatively charged through friction?
It is rubbed with another object, and electrons move onto the rod.
Which best describes an example of a p-type semiconductor?
It uses boron so that electrical conduction is due to the movement of a positive charge.
Cici uses a long extension cord to plug a lamp into a wall outlet in the next room. What effect will the extension cord have on the circuit?
It will increase the resistance in the circuit.
In a movie, the heroine saves the day by cutting a wire before the time runs out on a timer. How did she change the circuit?
She changed a closed circuit to an open circuit.
A positive rod is placed to the left of sphere A, and the spheres are separated. Which best describes the spheres?
Sphere A is negative and sphere B is positive because electrons from sphere B are attracted to the rod and move to sphere A.
The table lists the values of the electrical force and the gravitational force between two protons. How do the electrical force and the gravitational force compare?
The electrical force is 1.2 × 1036 times greater than the gravitational force, but only the gravitational force is attractive.
Which statements about electric field lines are correct? Check all that apply.
They point toward a negative charge. They point away from a positive charge. they never cross
Charges of +2 µC and +3 µC are 4 mm from each other. Raina's group draws four diagrams trying to represent the electrical force between the charges. Which diagram is correct?
W
Mark creates a graphic organizer to review his notes about electrical force. Which labels belong in the regions marked X and Y?
X: Decreasing to half will quadruple force Y: Doubling will double force
Wendy makes a graphic organizer to help herself apply Ohm's law to electric circuits. Which formulas belong in the regions marked X and Y?
X: Req = R1 + R2 + R3 Y: I =
The diagram shows a charge moving into an electric field. The charge will most likely leave the electric field near which letter?
Y
The diagram shows the electric field in the vicinity of a charge. One positive charge labeled Y. Vectors start perpendicular to the surface and spread out in all directions. Directly above is W. On the right is X and on the left is Z. The vectors are closer together below the charge and further apart above. At which point is the electric field strongest?
Y
Electric field lines can never cross. What would crossed electric field lines indicate?
a field pointing in two directions
Which best describes the materials that make up an electrical cord?
a metallic conductor with free electrons surrounded by a rubber insulator lacking free electrons
An electric field is represented by the force on which particle?
a positive test charge
A circuit that has only a single path for current to flow through is best classified into which category?
a series circuit
What is the unit for measuring electric current?
ampere
The diagram shows a transistor used in a circuit. What does the diagram show?
an NPN transistor used as an amplifier
In which type of transistor does current flow from the base to the emitter?
an NPN transistor, which has a p-type base
Angela sees a puzzle that uses a board with 20 holes drilled into it. There are 18 pegs in the holes, and the goal of the puzzle is to move the pegs by hopping them into the open holes until both holes are at one end of the board. How could Angela use the puzzle to model semiconductors?
as a p-type semiconductor with the pegs representing electrons and the holes representing positive charges
Liana draws a diagram to show the direction of the electric force acting on a charged particle in a uniform electric field. Which change would make the diagram correct
changing the force to point right
Which lists the layers in a PNP transistor from the least negative to the most negative?
emitter, base, collector
The area around a charged object that can exert a force on other charged objects is an electric
field
Which changes would cause an increase in the resistance of a wire? Check all that apply.
increasing its temperature using a longer wire using a thinner wire
What is the direction of the electric field at a point directly to the left of a positive charge, Q?
left
A positive charge, q1, of 5 µC is 3 × 10-2 m west of a positive charge, q2, of 2 µC. What is the magnitude and direction of the electrical force, Fe, applied by q1 on q2?
magnitude: 100 N direction: east
The diagram shows a transistor used in a circuit. The transistor in the circuit is used to
switch a current
Which is a dopant for a semiconductor that conducts electricity due to the movement of positive charges?
thallium
While teaching about transistors, Mrs. Kwon shows a video of a hand pump being used to draw water from a well. She points out how the person primes the pump by pouring a small amount of water into it before the water would start to flow. What does the water used to prime the pump represent?
the current in the base that turns the transistor on