30 quetions ...several questions were not answered on prior posts so reposting f
ID: 1624347 • Letter: 3
Question
30 quetions ...several questions were not answered on prior posts so reposting for last shot available....thanks
A bell is rung. What best describes the density of air around the bell?
The air density does not change.
The air density increases and then returns to normal levels.
The air density decreases and then returns to normal levels.
The air density increases and decreases repeatedly before returning to normal.
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Tony uses the device shown in the diagram to model how an electromagnet is used in his uncle’s scrap metal yard.
After picking up several staples with the device, what change would enable Tony to drop the staples in the scrap metal bin?
missing diagra of a nails with coils wrapped around it
coils extenting from a battery then wrapped around a nail....hope that makes sesnse,
removing the battery
removing the iron nail
moving the wire loops closer together
spreading the wire loops farther apart
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The diagram shows light passing through an opening and forming bands.
Which two order bands are the dimmest?
n = 0 and n = 1
n = 0 and n = 3
n = 1 and n = 2
n = 2 and n = 3
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A sound from a source has an intensity of 270 dB when it is 1 m from the source.
What is the intensity of the sound when it is 3 m from the source?
30 dB
90 dB
810 dB
2430 dB
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Which fields would most likely make use of spectroscopy techniques? Check all that apply.
food production
medical research
scientific research
space research
weather forecasting
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Which best explains why infrared waves are ineffective for treating cancer?
They have frequencies that are too high to kill cancer cells.
They have short wavelengths, which can be harmful to healthy cells.
They do not transfer enough energy to destroy cancer cells.
They have long wavelengths, which can be harmful to healthy cells.
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Which best describes the heat that you can feel on the engine of a running car?
The heat is unusable and absorbed by the engine.
The heat is usable and absorbed by the engine.
The heat is unusable and lost to the surroundings.
The heat is usable and lost to the surroundings.
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What is the resistance in a circuit that carries a 0.75 A current when powered by a 1.5 V battery?
0.50
1.1
2.0
2.3
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A boat moves up and down on a lake as a wave passes by. If the boat oscillates 10 times in 2 seconds, what is the period of the wave?
0.2 seconds
2 seconds
5 seconds
10 seconds
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A hot air balloon pilot wants the balloon to quickly rise several feet higher so it will be above some trees in the distance.
Which best explains how the pilot can make the balloon rise?
The pilot can adjust the temperature inside the balloon so it is equal to the temperature of the surrounding air.
The pilot can adjust the density of the air inside the balloon so it is equal to the density of the surrounding air.
The pilot can decrease the temperature inside the balloon so it is cooler than the surrounding air.
The pilot can increase the temperature inside the balloon so it is warmer than the surrounding air.
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Which are characteristics of a ray when it hits a boundary and reflects, but not when it hits the boundary and refracts? Check all that apply.
changes direction
changes speed
does not change direction
does not change speed
bounces off the boundary
passes through the boundary
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Which best explains why infrared waves are ineffective for treating cancer?
They have frequencies that are too high to kill cancer cells.
They have short wavelengths, which can be harmful to healthy cells.
They do not transfer enough energy to destroy cancer cells.
They have long wavelengths, which can be harmful to healthy cells.
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The electric field between two parallel plates has a magnitude of 180 N/C. The two plates are 2.5 cm apart. Recall that the magnitude of the charge on an electron is 1.602 × 10-19 C.
How much work is done to move an electron from the positive plate to the negative plate?
4.0 × 10-21 J
7.2 × 10-19 J
4.5 J
7200 J
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A –0.06 C charge that is pointing downward is placed in a uniform electric field with a strength of 200 N/C. What is the magnitude and direction of the force on the charge?
12 N up
12 N down
3333 N up
3333 N down
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Which diagram best illustrates the magnetic field of a bar magnet?
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What is the main difference between a permanent magnet and a temporary magnet?
A permanent magnet is made of a ferromagnetic material, while a temporary magnet is not.
A temporary magnet attracts only metal objects, while permanent magnets attract both metal objects and other magnets.
The domains in a temporary magnet easily lose alignment, but the domains in a permanent magnet keep their alignment.
There are domains in a permanent magnet, but not in a temporary magnet.
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Takumi works in his yard for 45 minutes each Saturday. He works in the morning, and he wears sunscreen and a hat each time he works in the yard.
What does Takumi hope to reduce through his actions?
the likelihood of stochastic effects, such as DNA mutations
the severity of stochastic effects, such as cancer
the severity of non-stochastic effects, such as cancer
the likelihood of non-stochastic effects, such as radiation sickness
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At night, the demand for electricity supplied by a fission nuclear reactor decreases. How is the fission nuclear reaction controlled to avoid overproduction of electricity?
The temperature of the reactor is lowered because high temperature and pressure are needed.
The temperature of the reactor is raised because the reaction slows down at higher temperatures.
The exposure between the fuel rods and a neutron-absorbing material is increased.
The exposure between the fuel rods and a neutron-absorbing material is reduced.
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Aluminum has a frequency threshold of 9.846 × 1014 Hz. Which best explains what will happen when light with a frequency below the frequency threshold strikes aluminum?
Electrons will be ejected immediately.
No electrons will be ejected.
Electrons will start being ejected several seconds after the light strikes the aluminum.
No electrons will be ejected unless the intensity is very high.
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An 8.0 cm object is 40.0 cm from a concave mirror that has a focal length of 10.0 cm. Its image is 16.0 cm in front of the mirror.
The height of the image produced by the mirror, to the nearest tenth, is cm.
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A system uses 2,380 J of energy to do work as 12,900 J of heat are added to the system.
The change in internal energy of the system is _________ J.
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A photon has a frequency of 7.3 × 10–17 Hz. Planck’s constant is 6.63 × 10–34 J•s.
The energy of the photon, to the nearest tenths place, is______ × 10–50 J
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Two identical waves are traveling toward each other in the same medium. One has a positive amplitude, meaning that its peaks only go upward, and the other wave has a negative amplitude, with peaks going downward.
What will occur when the waves peak at the same place at the same time?
constructive interference
destructive interference
a reflecting wave
wave refraction
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Which factors affect the strength of a magnetic field around a current-carrying wire? Check all that apply.
the type of metal of the wire
the amount of the current
the direction of the current
the temperature of the wire
the distance from the wire
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Which best explains why infrared waves are ineffective for treating cancer?
They have frequencies that are too high to kill cancer cells.
They have short wavelengths, which can be harmful to healthy cells.
They do not transfer enough energy to destroy cancer cells.
They have long wavelengths, which can be harmful to healthy cells.
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An 8.0 cm object is 40.0 cm from a concave mirror that has a focal length of 10.0 cm. Its image is 16.0 cm in front of the mirror.
The height of the image produced by the mirror, to the nearest tenth, is _____ cm.
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Which properties can be used to determine whether a substance is a liquid or a plasma? Check all that apply.
the mass of the substance
the container of the substance
the charge of the substance’s particles
the distance between the substance’s particles
the compressibility of the substance
the color of the substance
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A positive rod is touched to a neutral sphere.
Which best explains the arrow’s purpose in the diagram?
It is showing the direction that protons move in, making the sphere negative.
It is showing the direction that protons move in, making the sphere positive.
It is showing the direction that electrons move in, making the sphere positive.
It is showing the direction that electrons move in, making the sphere negative.
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What is the main difference between a permanent magnet and a temporary magnet?
A permanent magnet is made of a ferromagnetic material, while a temporary magnet is not.
A temporary magnet attracts only metal objects, while permanent magnets attract both metal objects and other magnets.
The domains in a temporary magnet easily lose alignment, but the domains in a permanent magnet keep their alignment.
There are domains in a permanent magnet, but not in a temporary magnet.
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Once started, why can nuclear fission continue to occur on its own?
The thermal energy released can cause the products to join.
The neutron formed by the reaction can cause more nuclei to combine.
The thermal energy released can cause the products to split.
A neutron begins the reaction, and more neutrons are formed in it.
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The diagram shows the electric field lines around two charges.
Based on the field lines, what is the best description of the charges?
a. They are negative, and they repel.
b. The left is negative and the right is positive, so they attract.
c. The left is positive and the right is negative, so they attract.
d. They are positive, and they repel.
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Sublimation involves a change from a solid, and vaporization involves a change from a liquid.
Sublimation results in a gas, and vaporization results in a liquid.
Sublimation involves the absorption of heat, and vaporization involves the release of heat.
Sublimation involves the release of heat, and vaporization involves the absorption of heat.
Explanation / Answer
1)When a bell is rung, the sound waves it produced are caused by the vibration of the molecules. Furthermore, the molecules from the metal of the bell continue to vibrate to the air surrounds it. Since the air has a much lower density, the sound can be easily propagated by molecules in it.
so the option is C
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