Quiz

QUIZ

1. What determines the direction that two freely hanging magnets of different sizes (two inches and one inch each in size) next to each other will hang?

a. The larger one will point to the north-seeking end to the north pole and the south-seeking end to the south pole while the smaller one will point opposite to the larger one. b. The two magnets will point east-west with opposite poles of the magnets attracting each other. c. Both will hang with their north-seeking end to the north pole but will hang as far apart from one another as they can. d. The magnets will swing around a central axis and neither will reach an equilibrium and hang without motion.

Answer: c. The earth’s magnetic field will be strong enough that they will hang in a north-south position but they will hang as far apart from one another as they can because their like poles will repel each other as long as the repulsive forces between them are strong enough.

2. How do you separate the north and south poles of a cylindrical magnet that is two inches in diameter?

a. Cut it in half b. Cut it lengthwise down the center of the cylinder into small slivers c. Cut it down to a single atom in length d. It is not possible to separate the poles

Answer: d. It is not possible to separate the poles of a magnet, even if you cut it down to a single atom in length because even the iron atom will have a magnetic north and magnetic south pole.

3. What happens to the forces on a charged particle in a magnetic field?

a. The forces will be greatest parallel to the direction of the field. b. The forces will be greatest toward the south pole of a magnet. c. The forces will be zero parallel to the direction of a magnetic field. d. The forces make it easier to cross magnetic lines than to travel along them.

Answer: c. The forces will be zero parallel to the direction of a magnetic field, which make charged particles more likely to travel along the field lines rather than cross them.

4. What is the Hall effect in magnetism?

a. It is the separation of charge across a conductor because of a magnetic field across it. b. It is the movement of charges along a conductor because of a magnetic field applied. c. It is the alignment of charges along magnetic field lines from positive to negative. d. It is the force that drives electrons and protons apart in atoms placed in an electric field.

Answer: a. The Hall effect is the separation of charge across a conductor because of a magnetic field applied across the conductor.

5. It has been established that wires can generate a magnetic field. What is the proportionality of the magnitude of this electric field?

a. It is proportional to the current and proportional to the distance from the wire. b. It is proportional to the current and inversely proportional to the distance from the wire. c. It is proportional to the square of the current and inversely proportional to the distance from the wire. d. It is proportional to the square root of the current and the distance from the wire.

Answer: b. There is a proportionality constant called the permeability of free space but the overall proportionality is that it is proportional to the current applied and inversely proportional to the distance from the wire.

6. What is the magnetic field like inside and outside a solenoid?

a. It is uniform and large inside the solenoid, while it is nearly zero outside of the solenoid. b. It is strongest in the middle of the solenoid and just outside of the solenoid, decreasing with distance. c. It is strongest at each end of the solenoid. d. It is independent of the number of turns of coil in the solenoid and is the same inside and outside the solenoid.

Answer: a. The magnetic field inside the solenoid will be uniform and large inside the solenoid, while it is nearly zero outside of the solenoid. It is dependent on the number of turns of coil in the solenoid.

7. What is measured in Henry units?

a. Electrical resistance b. Mutual inductance c. Change in current over time d. Magnetic field strength

Answer: b. The unit of the Henry involves mutual inductance, in which a high mutual inductance means that the change in current of one device can significantly change the emf of another device.

8. What is not true according to Maxwell’s equations?

a. A static charge will produce a magnetic field. b. Magnetic fields have no beginning and no end. c. Electric fields start at the positive end and end at the negative end. d. EMFs are created by changing magnetic fields.

Answer: a. These are true statements except that it is not true that a static charge will produce a magnetic field. It is the current and not the charge itself that produces the magnetic field.

9. Which type of electromagnetic wave has the highest frequency and the ability to carry more information?

a. AM radio waves b. Cable TV waves c. FM radio waves d. TV antenna waves

Answer: c. Cable and satellite TV waves will have higher frequencies and can deliver HD or high-definition TV by carrying more information in the wave.

10. What type of wave is used in the practical application of radar?

a. AM radio waves b. Microwaves c. Gamma waves d. Infrared waves

Answer: b. Radar is done by using microwaves that are transmitted and bounce back from weather systems; these types of waves can be seen in many practical applications around the earth.