General Physics II Final Exam

What do you call the property of attracting certain metals?

• Magnetic Field

• Magnetism

• Magnetic flux

• Magnetic force

Answer explanation

The property of attracting certain metals is known as magnetism. It refers to the physical phenomenon where materials exhibit attractive or repulsive forces due to their magnetic fields.

Which of the following is defined as the number of magnetic field through an area?

• Magnetic Field

• Magnetic Poles

• Magnetic flux

• Magnetic force

Answer explanation

Magnetic flux is defined as the total magnetic field passing through a given area. It quantifies the amount of magnetic field lines that penetrate that area, making it the correct choice.

What direction does the magnetic field lines draws in poles of the magnet?

• S-pole to N-pole

• N-pole to S-pole

• Either way

• N-N poles or S-S poles

Answer explanation

Magnetic field lines always flow from the North (N) pole to the South (S) pole of a magnet. Therefore, the correct answer is N-pole to S-pole, indicating the direction of the magnetic field.

A certain proton travels at v=15m/s in the +x-axis with a magnetic field β=3T pointing out of the page. What will be the direction of the force of the proton?

• Downward

• Upward

• Into the page

• Out of the page

Answer explanation

Using the right-hand rule, point your thumb in the direction of the proton's velocity (+x), and your fingers in the direction of the magnetic field (out of the page). Your palm then points upward, indicating the force direction on the proton.

A bar magnet is divided in two pieces. Which of the following statements is true about the force between the broken pieces if they face each other with a small separation?

• There is a magnetic attractive force between the broken pieces.

• There is a magnetic repulsive force between the broken pieces.

• There is a electric repulsive force between the broken pieces.

• There is no force between the broken pieces since they are demagnetized.

Answer explanation

When a bar magnet is cut, each piece retains its magnetic properties, creating a north and south pole. When the broken pieces face each other, the opposite poles attract, resulting in a magnetic attractive force between them.

Which of the following statements best explains why the total magnetic flux in a closed surface (volume) is zero?

• The number of magnetic field entering the surface is equal to the magnetic field leaving.

• All of the area in a closed surface has no magnetic flux because no magnetic field can enter a closed surface.

• There is no surface area when there is a closed surface.

• The total magnetic flux in a closed surface is zero but only sometimes, there are times when the magnetic flux can be maximum in very special situation.

Answer explanation

The correct choice states that the number of magnetic field lines entering a closed surface equals those leaving it, resulting in zero net magnetic flux. This is a consequence of the conservation of magnetic field lines.

Which of the following is happens when the magnetic flux changes?

• electromagnet induction

• electromotive force

• magnetic flux

• induced current

Answer explanation

When the magnetic flux changes, it induces electromagnet induction, which generates an electromotive force and can lead to induced current. Thus, the correct answer is electromagnet induction.

Which law states that the induced current flows in a direction such that it opposes the change which caused it?

• Ohm's Law

• Faraday's Law

• Lenz's Law

• Lorentz's Law

Answer explanation

Lenz's Law states that the induced current flows in a direction that opposes the change in magnetic flux that produced it. This principle is crucial in understanding electromagnetic induction.

In which of the situation does electromagnetic induction occur?

Answer explanation

Electromagnetic induction occurs when a changing magnetic field induces an electric current in a conductor. This can happen when a magnet moves relative to a coil or when the coil moves through a magnetic field.

Which of the following statements is not true about the EMF?

• the rate of change of magnetic flux causes the EMF to change

• EMF changes as the magnitude of magnetic field changes

• the speed of relative motion between the conductor and the magnet is a factor that affects EMF

• induced electromotive force is always constant so it does not change

Answer explanation

The statement 'induced electromotive force is always constant so it does not change' is not true. EMF varies with changes in magnetic flux, magnetic field strength, and the speed of motion between the conductor and the magnet.