Review: Electricity

A circuit consist of a singular resistor, R₁ and a 9-V battery. A second identical resistor, R₂ is added to the circuit in parallel with R₁. How does the potential difference across R₁ Chnage after R₂ is added?

• The potential difference decreases because a 9-V battery cannot handle the resistors in parallel.

• The potential difference decreases because two resistors in parallel can split the 9 V equally.

• The potential difference remains the same because resistors in parallel do not cause a change in voltage.

• The potential difference remains the same because resistors in parallel create extra current that balances the extra resistance.

The atoms of both copper and rubber contain protons and electrons; however, copper is more conductive than rubber. Why is copper able to conduct more electricty?

• Copper contains free electrons, and rubber contains bound electrons

• Rubber contains free electrons, and copper contains bound electrons.

• Copper contains free protons, and rubber contains bound protons.

• Rubber contains free protons, and copper contains bound protons.

Tags

NGSS.HS-PS1-3

A positive glass rod is placed near a neutral metallic sphere. If they do not touch, what happens to the charges inside the sphere?

• Like charges attract, which causes the sphere to become polarized

• unlike charges attract, which causes the sphere to become polarlized

• Like charges attract, which causes the sphere to become charged

• unlike charges attract, which causes the sphere to become charged

Tags

NGSS.HS-PS2-4

An electron losses 2.00 X 10^-15 J of energy traveling to the screen of a laptop computer. Why is the energy loss small?

• because the charge is small

• because the charge is large

• because the resistance is small

• because the resistance is large

How does the number of turns in an electromagnetic create a strong magnetic field?

• Each turn increases the amount of time it takes for the current to travel through the wire.

• Each turn decreases the amount of time it takes for the current to travel through the wire.

• Each turn increases the amount of induction produced by the current in the wire.

• Each turn decreases the amount of induction produced by the current in the wire.

Tags

NGSS.HS-PS2-5

Two current-carrying solenoids are placed near each other. Which would increase the amount of mutual inductance the pair of coils experiences?

• aligning the coils perpendicular to each other

• aligning the coils parallel to each other

• using only aluminum wiring

• using copper wiring

An electron beam enters a region between two oppositely charged electric plates, as shown in these diagrams. In which direction will the election beam bend?

• It will bend toward the negative plate

• It will bend toward the positive plate

• it will bend in the opposite direction of the way it is moving

• It will not bend and will continue to move into the same direction

Tags

NGSS.HS-PS2-4

NGSS.HS-PS3-5

Which statement explains an increase in efficiency from using alternating current instead of direct current in power-distributuion systems?

• Alternating current has electrons that move with the current flow, and direct current has electrons that do not move with the current flow.

• Alternating currents are used in low-voltage applications, whereas direct currents are used in high voltage applications.

• Alternating curents lose less power when transmitted through wires over long distances than direct currents do

• Alternating currents will not reverse the voltage and direction of the current flow, and direct currents will allow reverse voltage and current flow.

A circuit has a voltage source and three identical resistors in parallel. How will removing one of the resistors affect the voltage of the circuit?

• The voltage will stay the same because the voltage remains constant through parallel resistors.

• The voltage will increase by a factor of 2 because the voltage constantly increases through parallel resistors.

• The voltage will decrease by a factor of 2 because voltage is directly proportional to the number of parallel resistors a circuit contains.

• The voltage will increase by a factor of 3 because voltage is indirectly proportional to the number of parallel resistors a circuit contains.

A circuit contains a voltage source and four resistors connected in series. If the voltage is decreased by one-half, what will happen to the current flowing through the circuit?

• The current will decrease by one-fourth because current has an inverse relationship to the number of resistors that are in series.

• The current will decrease by one-half because current has a direct relationship to voltage of the circuit.

• The current will double because current has an inverse relationship to the voltage of the circuit.

• The current will quadruple because current has an direct relationship to the number of resistors that are in series.