8th Grade Science Review 16 (Electromagnetism)

Charged particles in the solar wind bombard Earth constantly. The image shows how the paths of these charged particles are bent as they approach Earth. What causes the charged particles in the solar wind to change course as they approach Earth?

• Earth’s gravity
  
• Earth’s radiation
  
• Earth’s electric field
  
• Earth’s magnetic field

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NGSS.HS-PS3-5

Which powerline would most likely have the highest voltage?

• The one supplying a residential area.
• The one near a power distribution center.
• The one near a power plant.
  
• The one along a highway.

A junkyard electromagnet is strong enough to pick up cars, but not trucks. How could it be upgraded to lift larger vehicles?

• The electric current and the number of coils in the solenoid could be increased.
• The electric current could be increased and the number of coils in the solenoid decreased.
• The electric current and the number of coils in the solenoid could be decreased.
• The electric current could be decreased and the number of coils in the solenoid increased.

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NGSS.HS-PS2-5

NGSS.HS-PS3-5

How could engineers remodeling a hydroelectric plant increase power output from the plant without replacing its magnet?

• Increase the current flowing to the magnet and the turbine.
  
• Increase the height of the dam so that water will flow faster.
• Add more electrical wires coming from the generator.
• Heat the water before it enters the generator.

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NGSS.HS-ETS1-3

Look at the solenoids and electromagnets. Identify which of them has the strongest magnetic field.

• A
• B
• C
• D

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NGSS.HS-PS2-5

NGSS.HS-PS3-5

The magnetic field of a solenoid can be increased by

• adding more loops per meter.
• increasing the current.
• putting an iron core inside the coil to make an electromagnet
• all of the above

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NGSS.HS-PS2-5

NGSS.HS-PS3-5

A student attaches a meter to a wire coil. Next, the student moves a magnet back and forth through the coil, as shown in the picture below.   As the magnet moves back and forth, the meter indicates

• volume
• temperature
• current
• conductivity

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NGSS.HS-PS2-5

A student is performing an investigation on electromagnets using the supplies shown below. The student wants to determine how the size of the nail affects the strength of the electromagnet. The student uses a different nail in each trial but keeps the same number of coils in the wire and uses the same battery. Which is the dependent variable in this investigation?

• type of battery
• size of nail
• number of coils in wire
• strength of electromagnet

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NGSS.HS-PS2-5

A student builds the electromagnet shown in the diagram below.
How can the student increase the strength of the magnetic field around the electromagnet?

• Remove the nail from within the coil.
• Use a wire with a smaller diameter.
• Increase the number of loops in the coil.
• Move the battery closer to the nail.

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NGSS.HS-PS2-5

Which statement best compares a permanent magnet and an electromagnet?

• A permanent magnet has a north pole and a south pole, but an electromagnet only has a south pole.
• A permanent magnet has a fixed magnetic field strength but the magnetic field strength of an electromagnet can be changed.
• A permanent magnet requires an external source of energy, but an electromagnet produces its own energy.
• The magnetic field lines from a permanent magnet emerge from the north pole, but they emerge from the south pole of the electromagnet.