Question 1

Two singly ionized isotopes,X and Y,of the same element move with the same speed perpendicular to a uniform magnetic field.Isotope X follows a path of radius 3.29 cm while isotope Y moves along a path 3.43 cm in radius.What is the ratio of the two isotope masses,

Accepted Answer

The answer of Two singly ionized isotopes,X and Y,of the...

Question 2

When a magnetic field causes a charged particle to move in a circular path,the only quantity listed below which the magnetic force changes significantly as the particle goes around in a circle is the particle's:

Accepted Answer

The magnetic force exerted on a charged particle moving in a magnetic field is given by F = q(v x B), where v is the velocity of the particle and B is the magnetic field. This force is perpendicular to both the velocity and the magnetic field, and thus it causes the charged particle to move in a circular path. 
The radius of the circular path depends on the velocity, mass, and charge of the particle, as well as the strength of the magnetic field. However, the momentum of the particle (p=mv) is conserved in the absence of external forces, and thus it remains constant as the particle moves in a circle. Therefore, the magnetic force does not change the momentum of the particle significantly as it goes around in a circle.

Question 3

A proton,which moves perpendicular to a magnetic field of 0.8 T in a circular path of radius 0.062 m,has what speed? (q_p = 1.6 × 10−¹⁹ C and m_p = 1.67 × 10−²⁷ kg)

Accepted Answer

The formula to calculate the speed of a charged particle moving in a circular path in a magnetic field is:

v = B*r*m^-1

where v is the speed of the particle, B is the magnetic field, r is the radius of the circular path, and m is the mass of the particle.

Substituting the values given in the question, we get:

v = 0.8*0.062*(1.67*10^-27)^-1

v = 4.8*10^6 m/s

Therefore, the correct answer is D) 4.8E+6 m/s.

Question 4

A deuteron,with the same charge but twice the mass of a proton,moves with a speed of 1.7 × 10⁵ m/s perpendicular to a uniform magnetic field of 0.36 T.Which of the paths described below would it follow? (q_p = 1.6 × 10−¹⁹ C and m_d = 3.34 × 10−²⁷ kg)

Accepted Answer

The answer of A deuteron,with the same charge but twice...

Question 5

A proton,mass 1.67 × 10−²⁷ kg and charge +1.6 × 10−¹⁹ C,moves in a circular orbit perpendicular to a uniform magnetic field of 0.66 T.Find the time for the proton to make one complete circular orbit.

Accepted Answer

The answer of A proton,mass 1.67 × 10−²⁷ kg and...

Question 6

The path of a charged particle moving parallel to a uniform magnetic field will be a:

Accepted Answer

When a charged particle moves parallel to a uniform magnetic field, it experiences no magnetic force, thus it continues to move in a straight line.

Question 7

A current in a long,straight wire produces a magnetic field.The magnetic field lines:

Accepted Answer

The magnetic field lines around a long, straight wire carrying an electric current form concentric circles that go around the wire. This is known as the right-hand rule, which states that if you wrap your right hand around the wire with your fingers pointing in the direction of the current, your thumb will point in the direction of the magnetic field lines. Therefore, choice D is the best choice.

Question 8

In a mass spectrometer,an ion will have a smaller radius for its circular path if:

Accepted Answer

The answer of In a mass spectrometer,an ion will have...

Question 9

An electron is moving at a speed of 5.1 × 10⁶ m/s at an angle of 23° with respect to a uniform magnetic field of 7.3 × 10^-4 T.What is the radius of the resulting helical path? (m_e = 9.11 × 10^-31 kg,q_e = 1.6 × 10^-19 C)

Accepted Answer

The answer of An electron is moving at a speed...

Question 10

A 71-m-long wire carrying a current of 4.9 A will be accompanied by a magnetic field of what strength at a distance of 0.090 m from the wire? (magnetic permeability in empty space µ₀ = 4π × 10−⁷ T⋅m/A)

Accepted Answer

The magnetic field at a distance r from a long straight wire carrying a current I can be calculated using the formula:
B = (µI)/(2πr), where µ is the magnetic permeability of the medium (in this case, in empty space), which is given as 4π×10−7 T⋅m/A. 
Substituting the given values, we get
B = (4π×10−7 T⋅m/A × 4.9 A)/(2π × 0.090 m) = 1.1×10−5 T
Thus, the magnetic field at a distance of 0.090 m from the wire is 1.1×10−5 T. Therefore, the correct choice is C.

Question 11

A proton moving with a speed of 2.9 × 10⁵ m/s perpendicular to a uniform magnetic field of 0.35 T will follow which of the paths described below? (q_p = 1.6 × 10−¹⁹ C and m_p = 1.67 × 10−²⁷ kg)

Accepted Answer

The magnetic force on a charged particle moving in a magnetic field is given by F = qvB, where q is the charge of the particle, v is its velocity, and B is the magnetic field strength. The direction of the force is perpendicular to both v and B. In this case, the proton is moving perpendicular to the magnetic field, so the force on it will be perpendicular to both its velocity and the magnetic field. This will cause the proton to move in a circular path. The radius of the circular path can be calculated using the formula r = mv/qB, where m is the mass of the particle. Plugging in the given values, we get r = (1.67 × 10−27 kg)(2.9 × 105 m/s)/(1.6 × 10−19 C)(0.35 T) = 0.9 cm. Therefore, the correct answer is B.

Question 12

At the Fermilab accelerator in Weston,Illinois,singly-charged ions with momentum 4.8 × 10−¹⁶ kg⋅m/s are held in a circular orbit of radius 0.8 km by an upward magnetic field.What B-field must be used to maintain the ions in this orbit? (qion = 1.6 × 10−¹⁹ C)

Accepted Answer

The answer of At the Fermilab accelerator in Weston,Illinois,singly-charged ions...

Question 13

A proton with initial kinetic energy E is moving in circular motion in a uniform magnetic field.When it has completed one eighth of a revolution,what is its kinetic energy?

Accepted Answer

The kinetic energy of a charged particle moving in a uniform magnetic field remains constant because the magnetic force does no work on the particle. Therefore, after one eighth of a revolution, the kinetic energy of the proton is still E.

Question 14

If a charged particle is moving in a uniform magnetic field,its path can be:

Accepted Answer

The path of a charged particle moving in a uniform magnetic field can be a straight line (if it moves parallel to the field lines), a circle (if it moves perpendicular to the field lines), or a helix (if it moves at an angle to the field lines).

Question 15

A high-voltage power line 26.9 m above the ground carries a current of 2722 A.What is the magnetic field due to the current directly underneath the power line? (µ₀ = 4π × 10−⁷ T⋅m/A)

Accepted Answer

The magnetic field due to a long straight current-carrying wire is given by B = (µ₀I)/(2πr). Substituting the given values: µ₀ = 4π × 10⁻⁷ T⋅m/A, I = 2722 A, and r = 26.9 m, we get B = (4π × 10⁻⁷ T⋅m/A × 2722 A)/(2π × 26.9 m) = 20.2 µT.

Question 16

The current in a long wire creates a magnetic field in the region around the wire.How is the strength of the field at distance r from the wire center related to the magnitude of the field?

Accepted Answer

The strength of the magnetic field around the wire is inversely proportional to the distance from the center of the wire. This is known as the inverse square law, where the field strength decreases proportionally to the square of the distance from the source. Therefore, the closer you are to the wire, the stronger the field will be.

Question 17

Two long parallel wires 10 cm apart carry currents of 4.2 A and 8.7 A in the same direction.Is there any point between the two wires where the magnetic field is zero?

Accepted Answer

The magnetic field due to the 4.2-A wire at a distance x from it is given by B1 = μ0*4.2/(2πx), where μ0 is the permeability of free space. The magnetic field due to the 8.7-A wire at the same distance is B2 = μ0*8.7/(2π(0.1-x)). The total magnetic field at that point is the vector sum of B1 and B2. We want to find the distance x where the total magnetic field is zero. This requires that B1 and B2 have equal magnitudes and opposite directions, or B1 = -B2. Solving for x gives x = 0.033 m or 3.3 cm, which is option C.

Question 18

A superconducting wire carries a current of 10 kA.Find the magnetic field at a distance of 2.0 m from the wire.(µ₀ = 4π × 10−⁷ T⋅m/A)

Accepted Answer

The answer of A superconducting wire carries a current of...

Question 19

Magnetism had been a known phenomenon for some time before its relation to electric currents was found.That a current in a wire produces a magnetic field was discovered by:

Accepted Answer

The discovery that a current in a wire produces a magnetic field was made by Hans Christian Oersted in 1820.

Question 20

An incredible amount of electrical energy passes down the funnel of a large tornado every second.Measurements at a distance of 11.95 km from a large tornado showed an almost constant magnetic field of 2.69 × 10−⁸ T associated with the tornado.What was the average current going down the funnel? (µ₀ = 4π × 10−⁷ T⋅m/A)

Accepted Answer

The magnetic field (B) and the formula for magnetic field generated by a current-carrying wire (B = µ0*I/(2*pi*r)) can be used to find the current going down the funnel.

First, convert the magnetic field measurement from tesla (T) to tesla-meter/ampere (T*m/A):
4*pi*10^-7 T*m/A = 1

2.69*10^-8 T * 11.95 km * 1000 m/km = 3220 T*m

Now use the equation B = µ0*I/(2*pi*r), where r is the distance from the funnel (11.95 km = 11,950 m) and solve for I:

I = 2*pi*r*B/µ0

I = 2*pi*11950 m * 3220 T*m / (4*pi*10^-7 T*m/A)

I = 1607 A

Therefore, the average current going down the funnel is approximately 1607 A, which corresponds to choice B.

Quiz 19: Magnetism Magnets

Two singly ionized isotopes,X and Y,of the same element move with the same speed perpendicular to a uniform magnetic field.Isotope X follows a path of radius 3.29 cm while isotope Y moves along a path 3.43 cm in radius.What is the ratio of the two isotope masses,

When a magnetic field causes a charged particle to move in a circular path,the only quantity listed below which the magnetic force changes significantly as the particle goes around in a circle is the particle's:

A proton,which moves perpendicular to a magnetic field of 0.8 T in a circular path of radius 0.062 m,has what speed? (qp = 1.6 × 10−19 C and mp = 1.67 × 10−27 kg)

A deuteron,with the same charge but twice the mass of a proton,moves with a speed of 1.7 × 105 m/s perpendicular to a uniform magnetic field of 0.36 T.Which of the paths described below would it follow? (qp = 1.6 × 10−19 C and md = 3.34 × 10−27 kg)

A proton,mass 1.67 × 10−27 kg and charge +1.6 × 10−19 C,moves in a circular orbit perpendicular to a uniform magnetic field of 0.66 T.Find the time for the proton to make one complete circular orbit.