Term
The word electron (for a negatively charged particle) is derived from:
-the ancient Greek word for “amber.”
-the T.V. show “Voltron: Defender of the Universe!”.
-Charles-Augustin Coulomb's experimental notes.
-the ancient Greek word for “sheep.” |
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Definition
| A. the ancient Greek word for “amber.” |
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Term
You remove the wrapper from a new CD. You try to throw away the negatively-charged wrapper but it sticks to your hand. Why?
-When you removed the wrapper from the CD, it removed electrons from your hand. Your hand is now positively charged and attracts the wrapper.
-When you removed the wrapper from the CD, it removed electrons from the CD case. Your hand is also negatively charged because it too removed electrons from the CD case as you unwrapped the CD. Since they are the same charge, your hand attracts the wrapper.
When you removed the wrapper from the CD, it removed electrons from the CD case. Your hand is must be wet, because the electrons want to flow into your hand and are attracted to the water.
-When you removed the wrapper from the CD, it removed electrons from the CD case. Your hand is neutral, but the charges in your hand can be polarized so that the wrapper is still attracted. |
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Definition
| D. When you removed the wrapper from the CD, it removed electrons from the CD case. Your hand is neutral, but the charges in your hand can be polarized so that the wrapper is still attracted. |
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Term
Who did experiments on electrostatic charges and in doing so, set the convention for “positive charge” and “negative charge”?
- Charles-Augustin Coulomb
-Robert J. Van de Graaff
- Nikola Tesla
-Benjamin Franklin |
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Definition
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Term
When you use energy to push like charges on a surface, your energy is stored as electrostatic potential energy. A common circuit component has two conducting surfaces called "plates" that store charge (usually with one storing positive charge and one storing negative charge). These plates are separated by an insulator. The component is called a:
-resistor.
-wire.
-capacitor.
-transformer. |
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Definition
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Term
It's a cold winter day. You are petting your roomate's cat Heathcliff by giving him long strokes from nose to tail. You notice that as you reach for his nose, sparks are transferred between your fingertips and the cat's nose. Which of the following would best prevent sparks from occurring while you pet the cat?
-petting the cat from tail to nose instead of from nose to tail.
-drying the air of the apartment by using a dehumidifier.
-wearing rubber gloves when you go to pet the cat.
-putting on some hand-lotion before you pet the cat. |
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Definition
| D. putting on some hand-lotion before you pet the cat. |
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Term
Materials such as metals that allow free charge movement are called:
-electrical insulators.
- semiconductors.
-batteries.
-electrical conductors. |
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Definition
| D. electrical conductors. |
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Term
You pull a cotton-shirt from the clothes-dryer and notice that a sock is stuck to the shirt. Which of the following is most likely to be false?
-The sock is wool.
-The sock and the sheet are oppositely charged.
-The sock is also cotton.
-The sock and the shirt were often in contact as they tumbled around the dryer. |
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Definition
| C. The sock is also cotton. |
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Term
When is the magnitude of the force between two negatively-charged items the greatest?
-The magnitude of the force doesn't depend on the distance between the objects.
-The magnitude of the force is greatest when the objects are close together.
-The magnitude of the force is greatest when the objects are far apart. |
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Definition
| B. The magnitude of the force is greatest when the objects are close together. |
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Term
Lightning is a quick flow of electric charge through air, also known as:
-an induced charge.
-an electrical field.
-a corona.
-an electrical discharge. |
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Definition
| D. an electrical discharge. |
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Term
You are in your car on a road that is slippery from the recent rain. Suddenly, a car fleeing a police officer goes in front of you and runs off the road, into a pole holding up some high-voltage power lines. The power lines waver and then start to fall towards your vehicle (the pole is not going to hit your car... but the lines will). As they fall, you realize you are:
-safe if you jump out of your car onto the road.
-safe as long as you stay in the car, but it doesn't matter what you touch inside or whether or not your window is open.
-dead, or at least pretty injured.
-safe if you stay inside your car, take your arms off the steering wheel and keep your window closed. |
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Definition
| B. safe as long as you stay in the car, but it doesn't matter what you touch inside or whether or not your window is open. |
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Term
In order for a battery to light a bulb, the wires must be connected from the positive terminal of the battery to one terminal of the bulb, and then from the other terminal of the bulb to the negative terminal of the battery. This configuration, where the circuit is continuous through the bulb and the battery, is known as:
-a closed circuit.
-a long circuit.
-an open circuit.
-a short circuit. |
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Definition
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Term
In the simulation John Travoltage, John become covered with free-moving particles when his rubber shoes rubbed on wool carpet. When he touched the knob, current flowed as an electrical spark (electrical discharge!) was seen. What were the particles, and what was the direction of current flow, using what's known as conventional current flow (which is described at the bottom of page 289 to the top of page 290)?
-The particles were protons, but conventional current flow is against the flow of positive charges and therefore points from the knob to John's hand.
-The particles were protons, and conventional current flow follows the direction of the protons from John's hand to the knob.
-The particles were electrons, but conventional current flow pretends there are positive charges moving in a current from the knob to John's hand.
-The particles were electrons, and conventional current flow follows the direction of electron flow from John's hand to the knob. |
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Definition
| C. The particles were electrons, but conventional current flow pretends there are positive charges moving in a current from the knob to John's hand. |
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Term
The SI unit for electric current is the:
-Coulomb (C).
-Franklin (F).
-Ohm (LaTeX: \Omega)
-Ampere (A). |
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Definition
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Term
When you use a 6-volt battery in a flashlight instead of a 3-volt battery, the current that flows through the bulb will be twice the original current, as long as the bulb is cool enough to have a constant resistance, meaning that it is in a region where it still follows:
-Watt's Law.
-Coulomb's law.
-Ohm's Law.
-Ampere's Law. |
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Definition
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Term
In a simple circuit, three components (light bulbs, LED's and/or resistors) are joined so that current from a single supply (such as a battery) will be separated between the components. In this configuration, the three components all still experience an identical voltage drops (equal to the voltage of the supply). This is an example of:
-a non-ohmic circuit.
-a short circuit.
-series circuit.
-parallel circuit. |
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Definition
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Term
The circuit component in a flashlight that is designed to EASILY allow you to arbitrarily have an open circuit or a closed circuit in that section of the electronics is called a:
-switch.
-battery.
-resistor.
-bulb. |
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Definition
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Term
Which of the following materials will experience a decrease in resistance as its temperature increases?
- a semi-conductor.
- a superconductor.
- a metal.
- an insulator. |
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Definition
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Term
Your friend dares you to place your dry finger on the terminals of a 9-V battery (completing the circuit). You dare your friend to place the terminals on his tongue. You shake hands and do the dares. Which of the statements below best describes the results?
- The voltage drop across your finger and your friends' tongue area is the same, but your friend's tongue has lower resistance and therefore a higher current. Your friend's tongue feels "tingly" while your finger feels nothing.
- The voltage drop across your finger and your friends' tongue area is the same, therefore ths current is the same. You both have the same "tingly" feeling.
- The voltage drop across your finger and your friends' tongue area is the same, but your finger has lower resistance and therefore a higher current. Your finger feels "tingly" but your friend's tongue feels nothing. |
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Definition
| A. - The voltage drop across your finger and your friends' tongue area is the same, but your friend's tongue has lower resistance and therefore a higher current. Your friend's tongue feels "tingly" while your finger feels nothing. |
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Term
Your laptop is receiving electrical power from an AC/DC converter. The current flows to your laptop in one of the coaxial wires, and back to the converter in another. Which of the wires (if either) has a higher current?
- The wire carrying current away from your computer has a higher current.
- The wire carrying current to your computer has a higher current.
- Both wires are carrying the same current. |
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Definition
| C. Both wires are carrying the same current. |
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Term
When will the most power be dispersed in a wire or light bulb filament?
- When the current is small and the electrical resistance is also low.
- When the current is high and the resistance is also large.
- When the current is low but the electrical resistance is large.
- When the current is high but the electrical resistance is low. |
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Definition
| B. When the current is high and the resistance is also large. |
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Term
While positive and negative electric charges can exist independently, magnetic particles do not; the phenomena of magnetism always exists with pairs of “north” with “south.” A single rod with a north and south is called:
- a magnetic dipole.
- an electric monopole.
- an electric dipole.
- a magnetic monopole. |
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Definition
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Term
Suppose you have a long bar magnet with a north pole at one end and a south pole at the other. If you carefully break it in half (without heating it), the two new ends will:
- Become electrically charged.
- Attract.
- Be neutral.
- Repel. |
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Definition
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Term
The forces between magnet poles increase as:
- the distance between the poles decreases or if either pole gets smaller.
- the distance between the poles increases or if either pole gets larger.
- the distance between the poles decreases or if either pole gets larger.
- the distance between the poles increases or if either pole gets smaller. |
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Definition
| C. the distance between the poles decreases or if either pole gets larger. |
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Term
| Which statement describes how magnetic poles interact via magneto-static forces? - South poles repel north poles and other south poles, but north poles attract other north poles. - North poles repel other north poles, south poles repel other south poles, but north poles and south poles attract. - North poles attract other north poles, south poles attract other south poles, but north poles and south poles repel. - North poles repel south poles and other north poles, but south poles attract other south poles. |
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Definition
| B. North poles repel other north poles, south poles repel other south poles, but north poles and south poles attract. |
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Term
A charged object can be brought near a second uncharged object but still attract it if the charges in the second object can be separated. A similar phenomena occurs in magnetism when you place a magnet on a fridge. Unaligned magnetic dipoles can be aligned, in a process known as:
-electromagnetism
- magnetic polarization.
- magnetic induction.
- magnetic charging. |
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Definition
| B. magnetic polarization. |
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Term
If you drop or heat a magnet, you can randomize the magnetic domains. This process is known as:
- ferromagnetism.
- magnetic polarization.
- demagnetization.
- electromagnetism. |
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Definition
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Term
Moving electric charges (i.e. currents) produce magnetic fields. When you use a coil of wire to produce a magnet, it is called:
- a magnetic flux.
- a ferromagnet.
- a magnetic pole.
- an electromagnet. |
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Definition
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Term
1 / 1 pts
You can visualize magnetic field lines by:
1) sprinkling iron filings in a magnetic field.
2) holding a compass to various locations in a magnetic field and drawing its alignment.
- 1 only.
- 2 only.
- Both 1 and 2.
- Neither 1 nor 2. |
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Definition
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Term
Electromagnets are used in:
1) a type of medical imaging procedure known as Magnetic Resonance Imaging (MRI).
2) a type of switch used in electrical circuits (such as those in doorbells) known as relay switches.
3) a type of materials characterization process known as Nuclear Magnetic Resonance (NMR).
4) a component used in AC power distribution known as a transformer.
- 1 and 3 only.
- 1, 2, 3, and 4.
- 4 only.
- 2 and 4 only. |
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Definition
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Term
The SI unit for magnetic field is:
- the Curie (Ci).
- the Ampere (A).
- the Tesla (T).
- the Ørsted (Ø). |
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Definition
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Term
Direct current (or DC) power distribution was promoted by:
- Michael Faraday.
- Nikola Tesla.
- Thomas Edison.
- George Westinghouse. |
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Definition
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Term
One of the reasons that DC power distribution lost the “War of Currents” was that electrons have to translate through long wires to get to homes, and power is lost through thermal heating in the wires... making it more difficult to get power to home appliances (like lightbulbs!). This problem would be solved if the wires could be made with materials with no electrical resistance. These materials are known as:
- superconductors
- superresistors
- transformers
- insulators |
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Definition
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Term
A loop of conductor opposes a change in magnetic flux through it. In order to keep the magnetic field constant, free charges in the conductor can move in currents, trying to create the original field (via an electromagnetic effect). This phenomenon is known as:
- Ohm's law
- Ampere's law
- Lenz's law
- Coulomb's law |
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Definition
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Term
A step-down transformer:
- has fewer primary turns than secondary turns, and therefore supplies a higher voltage to the secondary circuit than that of the primary supply.
- has fewer secondary turns than primary turns, and therefore supplies a lower voltage to the secondary circuit than that of the primary supply.
- has fewer secondary turns than primary turns, and therefore supplies a higher voltage to the secondary circuit than that of the primary supply.
- has fewer primary turns than secondary turns, and therefore supplies a lower voltage to the secondary circuit than that of the primary supply. |
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Definition
| B. has fewer secondary turns than primary turns, and therefore supplies a lower voltage to the secondary circuit than that of the primary supply. |
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Term
The US standard for voltage in household-wiring is:
- 120 Volts DC.
- 230 Volts AC at a frequency of 50 Hz (cycles per second).
- 170 Volts DC. |
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Definition
| C. 120 Volts AC at a frequency of 60 Hz (cycles per second). |
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Term
The US standard for voltage in household-wiring is:
- 120 Volts DC.
- 230 Volts AC at a frequency of 50 Hz (cycles per second).
- 170 Volts DC. |
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Definition
| C. 120 Volts AC at a frequency of 60 Hz (cycles per second). |
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Term
A device that converts mechanical energy into electrical energy is known as:
- a generator.
- a resistor.
- a diode.
- a motor. |
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Definition
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Term
Real transformers are not 100% efficient because:
1) energy/power is dispersed in the electrical resistance of the coils as heat.
2) energy/power is lost as heat as the material magnetizes and demagnetizes.
3) since the easily magnetized materials used in the core are also typically conductors, the core can develop internal currents called “eddy currents” that disperse energy/power as heat.
- 1, 2, and 3.
- 1 only.
- 3 only.
- 2 only. |
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Definition
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Term
| Modern exercise bicycles have settings that change the difficulty-level (increasing or decreasing the force you must exert and the power you expend over the duration of your workout). This equipment works because you are exercising to mechanically operate the input of an electrical generator... and you provide power to an electrical circuit. In order to increase the difficulty of your workout, you should connect this generator to: - The resistance of the circuit does not have an effect, as long as it is a complete circuit.. - a circuit with high electrical resistance. - a circuit with low electrical resistance. |
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Definition
| C. a circuit with low electrical resistance. |
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Term
What will happen when you drop a strong magnet down the length of a conducting (but non-magnetic) piping?
- It will fall with the acceleration of gravity ( i.e. 9.8 m/s2 down).
- It will fall with the acceleration less than that of gravity ( i.e. < 9.8 m/s2 down).
- It will fall with an acceleration greater than that of gravity ( i.e. a > 9.8 m/s2 down).
- It will accelerate up out of the pipe with an acceleration greater than that of gravity (i.e. a > 9.8 m/s2 upward!). |
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Definition
| B. It will fall with the acceleration less than that of gravity ( i.e. < 9.8 m/s2 down). |
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Term
Why is it useful to have an iron core in transformers (and in your classroom electromagnet)?
- Iron can be magnetized and therefore enhances the magnetic field that is created by the current carrying coils (of your electromagnet or in the primary coils of the transformer).
- Iron cannot be magnetized and therefore prevents any secondary effects of induced fields that would prevent operation of the transformer or electromagnet.
- Iron is a conductor and can carry a current through the core of the transformer or electromagnet thereby increasing its fields.
- Iron is important for your red blood cells and will help combat any cancer risks from operation of the transformer or electromagnet. |
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Definition
| A. Iron can be magnetized and therefore enhances the magnetic field that is created by the current carrying coils (of your electromagnet or in the primary coils of the transformer). |
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