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| 1 | Like magnetic poles repel each other, whereas unlike magnetic poles attract each other. |
 | A) | True |
| B) | False |
|
| 2 | Magnetic flux lines are drawn in such a way that the direction at any point is the same as the direction of the force exerted on a unit south pole placed at that point. |
| A) | True |
| B) | False |
|
| 3 | The weber is a unit of magnetic flux density. |
| A) | True |
| B) | False |
|
| 4 | An electron projected from right to left through a magnetic field directed into the page will be deflected downward. |
| A) | True |
| B) | False |
|
| 5 | The area of a hysteresis loop is a measure of flux density. |
| A) | True |
| B) | False |
|
| 6 | The right-hand rule can be used to determine the direction of a magnetic field surrounding a current-carrying conductor. |
| A) | True |
| B) | False |
|
| 7 | Two current-carrying conductors placed near each other will experience a force of attraction if their currents are oppositely directed. |
| A) | True |
| B) | False |
|
| 8 | The magnetic field lines for a solenoid are the same shape as those for a bar magnet. |
| A) | True |
| B) | False |
|
| 9 | A large hysteresis loop means a more efficient electromagnetic device. |
| A) | True |
| B) | False |
|
| 10 | Magnetic materials having a high permeability will generally have a low retentivity. |
| A) | True |
| B) | False |
|
| 11 | Which of the following is not a unit of magnetic induction of flux density? |
| A) | Weber per square meter |
| B) | Gauss |
| C) | Tesla |
| D) | Weber |
|
| 12 | Magnetic fields have no effect on |
| A) | electric charges at rest |
| B) | electric charges in motion |
| C) | permanent magnets at rest |
| D) | permanent magnets in motion |
|
| 13 | The magnetic flux density at a distance d from a long, current-carrying, straight wire is proportional to |
| A) | d |
| B) | 1/d |
| C) | d2 |
| D) | 1/d2 |
|
| 14 | Relative permeability is |
| A) | the ratio of flux density in a material to that for a vacuum |
| B) | large for paramagnetic materials |
| C) | small for ferromagnetic materials |
| D) | equal to 4π x 10-7 T . m/A for a vacuum |
|
| 15 | The current through a wire is directed into the page. If a magnetic field is directed from right to left, the force on the wire will be |
| A) | to the right |
| B) | to the left |
| C) | upward |
| D) | downward |
|
| 16 | An electron is projected from left to right into a flux density of 0.3 T directed into the paper. If the speed of the electron is 2 x 106 m/s, the magnetic force
will be |
| A) | 9.6 x 10-14 N |
| B) | 6.9 x 10-14 N |
| C) | 6.9 x 10-14 N |
| D) | 4.8 x 10-14 N |
|
| 17 | A proton (+1.6 x 10-19 C) is projected from left to right at a velocity of 2 x 106 m/s. If an upward force of 1 x 10-13 N is observed, the magnetic flux density perpendicular to the velocity is approximately |
| A) | 1.25 T out of the paper |
| B) | 1.25 T into the paper |
| C) | 0.31 T out of the paper |
| D) | 0.31 T into the paper |
|
| 18 | A rectangular loop of wire 20 cm wide and 30 cm long makes an angle of 40° with a magnetic flux density of 0.3 T. The flux penetrating the loop is approximately |
| A) | 0.01 Wb |
| B) | 0.02 Wb |
| C) | 2 Wb |
| D) | 115 Wb |
|
| 19 | The magnetic induction at a distance of 6 cm in air from a long, currentcarrying conductor is 12 x 10-6 T. The current in the wire is |
| A) | 1.8 A |
| B) | 3.6 A |
| C) | 4.8 A |
| D) | 6.4 A |
|
| 20 | A solenoid has 60 turns of wire and a length of 16 cm and supports a current of 10 A. The relative permeability of the core is 1200. The magnetic induction at the center is approximately |
| A) | 1.4 T |
| B) | 2.83 T |
| C) | 5.65 T |
| D) | 11 T |
|
| 21 | Hysteresis is the lagging of the behind the . |
|
| 22 | According to the right-hand rule, if a current-carrying wire is grasped with the right hand so that the thumb points in the direction of the , the curled fingers of that hand point in the direction
of . |
|
| 23 | A circular coil in the plane of the paper supports a clockwise electric current. The direction of the magnetic flux near the center is . |
|
| 24 | The relative permeability of a material is the ratio of its to that for a(n) . |
|
| 25 | refers to the condition under which all the magnetic domains in a material are aligned. |
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| 26 | The unit of flux density in the metric system of units is the , and the unit of magnetic flux is the . |
|
| 27 | In applying the right-hand screw rule for magnetic effects on a conducting wire, the is turned into the . Then the direction of the will be the same as the direction of
advance of a right-hand screw. |
|
| 28 | A magnetic field having a flux density of one tesla will exert a force of one on a charge of one moving perpendicular to the field with a velocity of one . |
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| 29 | Materials with a relative permeability slightly less than unit are said to be ; materials have permeabilities slightly greater than unity. |
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| 30 | The ability of some materials to retain magnetism after the magnetizing force has been removed is referred to as . |