Ch2 L2 - Magnetic Field due to a Current in a Solenoid

A solenoid has a length of 5.3 cm and consists of 80 turns of wire. The wire carries a constant current of 3.1 A. Calculate the strength of the magnetic field at the center of the solenoid.

A solenoid that has length 𝐿 and 𝑁 turns is connected to a battery that has emf V.What would happen to the magnetic flux density at its axis if we compressed the solenoid to decrease its length to half?

• The magnetic flux density would double.

• The magnetic flux density would stay the same.

• The magnetic flux density would halve.

• There is not enough information to determine the answer.

In the figure, a solenoid has a length of 0.3 m,240 turns, and a resistance of 9 Ω.The solenoid is connected to a circuit as shown below. The ratio of the magnetic flux density when the switch (K) is closed to the magnetic flux density when the switch (K) is open is

• 11/8

• 11/20

• 20/11

• 8/11

In the figure, the two solenoids, a and b, have the same number of turns and carry equivalent direct currents. The ratio of the magnetic flux density of coil a to the magnetic flux density of coil b is

• 2/1

• 1/2

• 1/1

• The ratio cannot be determined from the given information.

• The current is equal to 7.5 A and passes from b to a.

• The current is equal to 15 A and passes from a to b.

• The current is equal to 15 A and passes from b to a.

• The current is equal to 7.5 A and passes from a to b.

A solenoid of negligible resistance that has length 𝐿 and 𝑁 turns that is uniformly distributed is connected to a circuit. What would happen to the magnetic flux density at the solenoid’s axis if half its length was cut and the remaining part was connected to the same circuit?

• The magnetic flux density would stay the same.

• The magnetic flux density would double.

• The magnetic flux density would halve.

• There is not enough information to determine the answer.

A solenoid that has length 𝐿 and 𝑁 turns is connected to a battery that has emf V.What would happen to the magnetic flux density at its axis if we compressed the solenoid to decrease its length to half?

• The magnetic flux density would halve.

• The magnetic flux density would not change.

• There is not enough information to determine the answer.

• The magnetic flux density would double.

A wire that carries a constant current of 0.24 A is formed into a solenoid with 12 turns per centimeter. Calculate the strength of the magnetic field at the center of the solenoid