Unit 5 Post Test: Magnetism

Select the Correct Answer

• an interaction between a magnetic south pole and a north pole

• an interaction between two magnetic south poles

• an interaction between two magnetic north poles

Select the correct answer.

What is the direction of magnetic field lines inside any magnet?

• They travel from north to south.

• They travel from south to north.

• They travel in a loop.

Why is a magnetic field a vector quantity?

• directional force

• directional speed

• specified location

How are magnetic poles and electrical charges similar?

• Their same forces repel each other, and their opposite forces attract each other.

• Their same forces attract each other, and their opposite forces repel each other.

• Magnetic force is equal to electric force.

When is the magnetic field the strongest?

• 
  when the field lines are far apart

• when the field lines are close together

• when the field lines are longer

A proton travels at right angles through a magnetic field of 0.025 tesla's. If the magnitude of the magnetic force on the proton is 1.8 × 10^-14 newtons, what is the velocity of the proton? The value of q = 1.6 × 10^-19 coulombs.

• 1.8 × 10⁵ meters/second

• 2.5 × 10⁶ meters/second

• 4.5 × 10⁶ meters/ second

One beam of electrons moves at right angles to a magnetic field. The force on these electrons is 4.9 × 10^-14 newtons. A second beam travels at the same speed, but at a 30° angle with the magnetic field. What force is on these electrons?

• (4.9 × 10^-14 newtons) · tan(30°)

• (4.9 × 10^-14 newtons) · sin(30°)

• (4.9 × 10^-14 newtons) · cos(30°)

A positive charge is moving from the floor of a room toward the ceiling. A magnetic field runs from east to west. In what direction is the magnetic force on the moving positive charge?

• toward the north

• toward the south

• toward the east

What is the magnetic force acting on an electron if its speed is 3.0 × 10⁶ meters/second and the direction is perpendicular to a magnetic field of 0.020 teslas? The value of q = -1.6 × 10^-19 coulombs.

• F = 0 newtons

• F = -6.0 × 10^-15 newtons

• F = -9.6 × 10^-15 newtons

What is the difference between the fields surrounding a stationary charge and those that surround a moving charge?

• A moving charge has only an electric field and a stationary charge has only a magnetic field.

• A moving charge has both an electric and magnetic field and a stationary charge has only an electric field.

• A moving charge has only a magnetic field and a stationary charge has both an electric and a magnetic field.