When the number of turns in a solenoid and its length are both doubled, the ratio of the magnitude of the new magnetic field inside to the magnitude of the original magnetic field inside is:
A: 0.25
B: 0.50
C: 1
D: 2
E: 4
A: 0.25
B: 0.50
C: 1
D: 2
E: 4
举一反三
- 1) What happens to the magnitude of the magnetic field inside a long solenoid if the current is doubled? A: It becomes four times larger. B: It becomes twice as large. C: It is unchanged. D: It becomes one-half as large. E: It becomes one-fourth as large.
- When the medium is magnetized, the molecular magnetic moment inside the paramagnetic material turns to the opposite direction of the external magnetic field
- When the medium is magnetized, the molecular magnetic moment inside the paramagnetic material turns to the opposite direction of the external magnetic field A: 正确 B: 错误
- There is no magnetic field in an ideal conductor, but there is a magnetic field inside because of the surface current。
- 5) Which one of the glowing magnetic field gives the largest magnitude? A: the field 2 cm away from a long, straight wire carrying a current of 3 A B: the field at the center of a flat, compact, circular coil, 2 cm in radius, with 10 turns, carrying a current of 0.3 A C: the field at the center of a solenoid 2 cm in radius and 200 cm long, with 1000 turns, carrying a current of 0.3A D: the field at the center of a long, straight, metal bar, 2 cm in radius, carrying a current of 300 A E: a field of 1 mT