8th Exam - Magnetic and Electrical fields

Magnetic fields are created by _______ electric charges.

• only positive
• only negative
• moving
• static

Tags

NGSS.MS-PS2-3

NGSS.MS-PS2-5

Cameron and Morgan are each holding a bar magnet with opposite poles facing each other. They walk in opposite directions until they stop feeling their magnet pull towards the other one. What can they conclude about the distance between them when they stop feeling their magnets pull?

• They are outside the magnetic field of their magnets.

• The distance made the magnets' force stronger.

• The magnetic fields are far enough apart to change direction.

• The magnetic field was weaker when they were close.

Tags

NGSS.MS-PS2-3

NGSS.MS-PS2-5

Why is a compass needle attracted to the northern part of Earth?

• Wind is stronger in the northern part of Earth

• It is being attracted to the Magnetic South Pole

• It is being attracted to the Magnetic North Pole

• It is broken

What actions can be taken to increase the strength of your electromagnet?

• Increasing Current

• Increasing number of coils/turns in a coil

• Coiling the current around a magnetic iron core

• Decreasing length of the coils

Match the variables with what they represent. ε = ​ (a)   , N = ​ (b)   , dΦ =​ (c)   ​ , dt = ​ (d)  

• Electromotive force
• Number of coils
• change in magnetic flux
• change in time
• Newtons
• number of magnets
• change in electric charge
• change in direction

Tags

NGSS.MS-PS2-3

Correctly identify what each variable in Coulomb's Law represents. F =​ (a)   , k =​ (b)   , q1/2 =​ (c)   , r =​ (d)  

• Electrical force
• Coulomb's constant
• charge
• radius
• friction
• gravitational constant
• quarks
• resistance

Tags

NGSS.HS-PS2-4

What is a way in which gravitational fields, electric fields, and magnetic fields are all alike?

• They affect only charged objects.

• They affect only objects that contain iron.

• Their effect weakens as the combined mass of the objects increases.

• Their effect weakens as the distance between the objects increases.

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NGSS.MS-PS2-5

Which forces can be either attractive or repulsive?

• electrical but not gravitational or magnetic

• gravitational but not magnetic or electrical

• magnetic and electrical but not gravitational

• electrical and gravitational but not magnetic

What happens when two north poles of a magnet are placed together?

• they repel
• they attract
• they cancel each other out
• the strength of the magnet is doubled

Tags

NGSS.MS-PS2-3

The closer the charges, the ___________ the force between them

• closer
• further
• stronger
• weaker

Tags

NGSS.HS-PS2-4