Question 1

The planetary model of the hydrogen atom consists of an electron in a circular orbit about a proton.The motion of the electron of charge 1.60 *10 ^- ¹⁹ C creates an electric current.The radius of the electron orbit is 5.30 *10 ^- ¹¹ m and the electron's velocity is 2.20 * 10⁶ m/s.What is the magnetic field strength at the location of the proton?

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Question 2

A superconducting wire carries a current of 1.0 * 10⁴ A.Find the magnetic field at a distance of 1.0 m from the wire.

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Question 3

At what speed would a proton need to circle the Earth at a height of 1 000 km above the equator if the Earth's magnetic field is horizontal and directed north-south,with an intensity of 4.00 *10 ^- ⁸ T? (The radius of the Earth is 6 400 km and the charge and mass of the proton are q = 1.60 *10 ^- ¹⁹ C and m_p = 1.67 * 10 ^- ²⁷ kg.Ignore relativistic corrections. )

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Question 4

On the average,in a ferromagnetic domain permanent atomic magnetic moments are aligned ____ to one another.

Accepted Answer

In a ferromagnetic domain, permanent atomic magnetic moments are aligned parallel to one another, leading to a net magnetic moment for the entire domain. This alignment can be induced by an external magnetic field or by the interactions between neighboring atomic moments.

Question 5

Which of the following type(s)of materials is(are)repelled when a magnet is brought near by?

Accepted Answer

Diamagnetic materials are repelled by magnets. Paramagnetic and ferromagnetic materials are attracted by magnets.

Question 6

A 0.50-m long solenoid consists of 1 000 turns of copper wire wound with a 4.0 cm radius.When the current in the solenoid is 18 A,the magnetic field at a point 1.0 cm from the central axis of the solenoid is

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Question 7

An ideal solenoid of radius a has n turns per unit length and current I.The magnetic flux $\phi$ _B through any circular area of radius a inside the solenoid,centered on and perpendicular to the solenoid axis is

Accepted Answer

The magnetic field inside a solenoid is given by B = μnI. 
The magnetic flux through a circular area of radius a and perpendicular to the solenoid axis is given by Φ = Bπa^2.
Substituting the value of B, we get Φ = μnIπa^2.
Therefore, option C is the correct answer.

Question 8

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:

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Question 9

What current in a solenoid 15.0-cm long wound with 100 turns would produce a magnetic field equal to that of the Earth,5.00 *10 ^- ⁵ T?

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Question 10

A stream of electrons passes through a velocity filter where the crossed magnetic and electric fields are 0.020 T and 5.00 * 10⁴ V/m,respectively.Find the kinetic energy (in electron volts)of the electrons passing through the filter.[1 eV = 1.60 *10 ^- ¹⁹ J]

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Question 11

A long solenoid (1 000 turns/m)carries a current of 25 mA and has an inside radius of 2.0 cm.A long wire which is parallel to and 4.0 cm from the axis of the solenoid carries a current of 6.0 A.What is the magnitude of the magnetic field at a point on the axis of the solenoid?

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Question 12

A magnetic field of 2.00 T is applied to a bubble chamber to make the tracks of protons and other charged particles identifiable by the radius of the circles they move in.If a high-energy proton moves along an arc of a 3.30-m circle,what is the momentum of the proton? [q = 1.60 *10 ^- ¹⁹ C,m = 1.67 *10 ^- ²⁷ kg]

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Question 13

An ideal solenoid of radius a has n turns per unit length and current I.The magnetic flux $\phi$ _B through any area completely inside the solenoid,centered on the solenoid axis but at a 45$\degree$angle to the axis,so that it touches the inside of the solenoid,as shown below,is

Accepted Answer

The flux through any surface that is completely inside the solenoid and parallel to its axis is given by 
Φ = μ0nIA,
where μ0 is the permeability of free space, n is the number of turns per unit length, I is the current, and A is the area of the surface. 
Here, the surface is at an angle of 45° to the axis, but it still touches the inside of the solenoid. So, we can consider the component of A that is parallel to the axis of the solenoid, which is A cos 45° = A/√2. 
Therefore, 
Φ = μ0nI(A/√2) = (μ0nIA/√2). 
Substituting the given values, we get 
Φ = (4π×10-7)(nI)(πa2/2√2) = (π2a2nI/2√2). 
Hence, the answer is (C).

Question 14

When a ferromagnetic material that has been magnetized is brought to a temperature greater than the Curie temperature,what happens to its residual magnetism.

Accepted Answer

When a ferromagnetic material is brought to a temperature greater than the Curie temperature, its thermal energy overcomes the alignment of magnetic domains and they become randomized, causing the material to lose its magnetization. Therefore, the residual magnetism disappears in this case.

Question 15

Two wires,each having a weight per unit length of 1.0 *10 ^- ⁴ N/m,are strung parallel,one 0.10 m above the other.If the wires carry the same current,though in opposite directions,how great must the current in each wire be for the magnetic field of the lower conductor to balance the weight of the upper conductor?

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Question 16

A long solenoid (n = 80 turns/cm)carries a current of 70 mA.Determine the magnitude of the magnetic field inside the solenoid.

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Question 17

A solenoid consists of 100 circular turns of copper wire.Parts of three turns,A,B and C,are shown below.  When a current flows through the coil,

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Quiz 22: Magnetic Forces and Magnetic Fields

A superconducting wire carries a current of 1.0 * 10⁴ A.Find the magnetic field at a distance of 1.0 m from the wire.

On the average,in a ferromagnetic domain permanent atomic magnetic moments are aligned ____ to one another.

Which of the following type(s) of materials is(are) repelled when a magnet is brought near by?

A 0.50-m long solenoid consists of 1 000 turns of copper wire wound with a 4.0 cm radius.When the current in the solenoid is 18 A,the magnetic field at a point 1.0 cm from the central axis of the solenoid is

An ideal solenoid of radius a has n turns per unit length and current I.The magnetic flux $\phi$ _B through any circular area of radius a inside the solenoid,centered on and perpendicular to the solenoid axis is

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:

What current in a solenoid 15.0-cm long wound with 100 turns would produce a magnetic field equal to that of the Earth,5.00 *10 ^- ⁵ T?

A stream of electrons passes through a velocity filter where the crossed magnetic and electric fields are 0.020 T and 5.00 * 10⁴ V/m,respectively.Find the kinetic energy (in electron volts)of the electrons passing through the filter.[1 eV = 1.60 *10 ^- ¹⁹ J]

A long solenoid (1 000 turns/m) carries a current of 25 mA and has an inside radius of 2.0 cm.A long wire which is parallel to and 4.0 cm from the axis of the solenoid carries a current of 6.0 A.What is the magnitude of the magnetic field at a point on the axis of the solenoid?

When a ferromagnetic material that has been magnetized is brought to a temperature greater than the Curie temperature,what happens to its residual magnetism.

A long solenoid (n = 80 turns/cm)carries a current of 70 mA.Determine the magnitude of the magnetic field inside the solenoid.

A solenoid consists of 100 circular turns of copper wire.Parts of three turns,A,B and C,are shown below. When a current flows through the coil,

Quiz 22: Magnetic Forces and Magnetic Fields

A superconducting wire carries a current of 1.0 * 104 A.Find the magnetic field at a distance of 1.0 m from the wire.

On the average,in a ferromagnetic domain permanent atomic magnetic moments are aligned ____ to one another.

Which of the following type(s) of materials is(are) repelled when a magnet is brought near by?

A 0.50-m long solenoid consists of 1 000 turns of copper wire wound with a 4.0 cm radius.When the current in the solenoid is 18 A,the magnetic field at a point 1.0 cm from the central axis of the solenoid is

An ideal solenoid of radius a has n turns per unit length and current I.The magnetic flux ϕ\phiϕ B through any circular area of radius a inside the solenoid,centered on and perpendicular to the solenoid axis is

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:

What current in a solenoid 15.0-cm long wound with 100 turns would produce a magnetic field equal to that of the Earth,5.00 *10 - 5 T?

A stream of electrons passes through a velocity filter where the crossed magnetic and electric fields are 0.020 T and 5.00 * 104 V/m,respectively.Find the kinetic energy (in electron volts)of the electrons passing through the filter.[1 eV = 1.60 *10 - 19 J]

A long solenoid (1 000 turns/m) carries a current of 25 mA and has an inside radius of 2.0 cm.A long wire which is parallel to and 4.0 cm from the axis of the solenoid carries a current of 6.0 A.What is the magnitude of the magnetic field at a point on the axis of the solenoid?

An ideal solenoid of radius a has n turns per unit length and current I.The magnetic flux ϕ\phiϕ B through any area completely inside the solenoid,centered on the solenoid axis but at a 45 °\degree° angle to the axis,so that it touches the inside of the solenoid,as shown below,is

When a ferromagnetic material that has been magnetized is brought to a temperature greater than the Curie temperature,what happens to its residual magnetism.

A long solenoid (n = 80 turns/cm)carries a current of 70 mA.Determine the magnitude of the magnetic field inside the solenoid.

A solenoid consists of 100 circular turns of copper wire.Parts of three turns,A,B and C,are shown below. When a current flows through the coil,

A superconducting wire carries a current of 1.0 * 10⁴ A.Find the magnetic field at a distance of 1.0 m from the wire.

An ideal solenoid of radius a has n turns per unit length and current I.The magnetic flux $\phi$ _B through any circular area of radius a inside the solenoid,centered on and perpendicular to the solenoid axis is

What current in a solenoid 15.0-cm long wound with 100 turns would produce a magnetic field equal to that of the Earth,5.00 *10 ^- ⁵ T?

A stream of electrons passes through a velocity filter where the crossed magnetic and electric fields are 0.020 T and 5.00 * 10⁴ V/m,respectively.Find the kinetic energy (in electron volts)of the electrons passing through the filter.[1 eV = 1.60 *10 ^- ¹⁹ J]