HS Electricity & Magnetism

Jonathan models two kinds of circuits containing identical bulbs and batteries. If one of the bulbs in each circuit breaks, which of the following explains what would happen to the rest of the bulbs?

• Electrons would stop flowing in all bulbs of circuits A and B.

• The flow of electrons would stop in all bulbs of circuit A but not of circuit B.

• The flow of electrons would stop in all bulbs of circuit B but not of circuit A.

• Electrons would stop flowing only in the broken bulbs of circuits A and B.

Which describes the flow of current in the series circuit shown?

• A. The current flows from the negative terminal of the battery, through both light bulbs at the same time, and back to the positive terminal of the battery.

• B. The current flows from the positive terminal of the battery, through both light bulbs at the same time, and back to the negative terminal of the battery.

• C. The current flows from the negative terminal of the battery, through the first light bulb, then through the second light bulb, and back to the positive terminal of the battery.

• D. The current flows from the positive terminal of the battery, through the first light bulb, then through the second light bulb, and back to the negative terminal of the battery.

During an electricity investigation, a student stated, "When the voltage increases current increases." Which equation can be used to justify this claim?

• I = V/R

• R = VI

• V = R/I

• I = R/V

If a circuit has a current of 0.25 A and a voltage of 3 V, how much resistance is in the circuit?

• 0.083 ohms

• 0.75 ohms

• 1.5 ohms

• 12 ohms

Mary wants to investigate the relationship between magnetism and the movement of an electrical charge. She has a coil of wire hooked to an ammeter to measure current. She has a moveable magnet inside the coil. As she moves the magnet within the coil, the ammeter indicates a certain current. Mary wants to increase the amount of current from the device. Which action would be the BEST to increase the current and why?

• A. Use a differently shaped magnet, because it would increase the magnetic field.

• B. Increase the diameter of coil, because more of the magnetic field will be included.

• C. Reduce the number of coils because this would increase the effect of the magnetic field.

• D. Move the magnet faster within the coil, because this will increase the rate of change of the magnetic field.

Which of the following works BEST for household wiring?

• A. A series circuit, with a circuit breaker for stopping the flow of current in an electric circuit as a safety measure.

• B. A parallel circuit, with a surge protector for stopping the flow of current in an electric circuit as a safety measure.

• C. A series circuit, with a surge protector for stopping the flow of current in an electric circuit as a safety measure.

• D. A parallel circuit, with a circuit breaker to stop the current flow in an electric circuit as a safety measure.

A classmate claims that as voltage increases, the current must increase as well. Which of the following calculations could be used to support this claim?

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A student creates an electric circuit model containing identical light bulbs. Which light bulbs MUST be unscrewed to stop the flow of current in the whole circuit and why?

• Light bulb P because it is connected by a series connection.

• Light bulb O because it is connected by a series connection.

• Light bulb M because it is connected by a parallel connection.

• Light bulbs M and N because they are connected in parallel connections.

Henry investigates how the flow of electricity produces magnetism. He follows this procedure. Since only two paper clips adhered to the nail, which action would BEST make the electromagnet attract more paper clips?

• A. Replace the nail with a pencil.

• B. Increase the number of coils of insulated wire.

• C. Connect an on/off switch between the battery and the nail.

• D. Reverse the direction of the positive and negative poles of the battery.

A student creates an electromagnetic wave and then reverses the direction of the current. Which of the following will happen to the magnetic field?

• The direction of the magnetic field will reverse.

• The magnetic field will expand.

• The magnetic field will be cancelled out and disappear.

• The magnetic field will cause the voltage of the battery to be reduced.