Question 1

The right-hand rule allows one to find a property of the interaction of a magnetic field with a charged particle.The right-hand rule applied to moving charges:

Accepted Answer

A) results in positive charges moving clockwise. 
B) results in negative charges moving clockwise. 
C) can be used for positive charges only. 
D) gives the direction of the force on a charge moving in a magnetic field. 
A) results in positive charges moving clockwise. 
B) results in negative charges moving clockwise. 
C) can be used for positive charges only. 
D) gives the direction of the force on a charge moving in a magnetic field.

Question 2

An incredible amount of electrical energy passes down the funnel of a large tornado every second.Measurements at a distance of 12.8 km from a large tornado showed an almost constant magnetic field of 2.35 × 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

A) 3.0E+3 A 
B) 1.5E+3 A 
C) 7.5E+2 A 
D) 9.6E+2 A 
E) 4.7E+3 A 
A) 3.0E+3 A 
B) 1.5E+3 A 
C) 7.5E+2 A 
D) 9.6E+2 A 
E) 4.7E+3 A

Question 3

A proton and a deuteron are moving with equal velocities perpendicular to a uniform magnetic field.A deuteron has the same charge as the proton but has twice its mass.The ratio of the acceleration of the proton to that of the deuteron is:

Accepted Answer

A) 0.5. 
B) 1. 
C) 2. 
D) There is no acceleration in this case. 
A) 0.5. 
B) 1. 
C) 2. 
D) There is no acceleration in this case.

Question 4

A circular loop carrying a current of 1.25 A is oriented in a magnetic field of 0.22 T.The loop has an area of 0.10 m2 and is mounted on an axis,perpendicular to the magnetic field,which allows the loop to rotate.If the plane of the loop is oriented parallel to the field,what torque is created by the interaction of the loop current and the field?

Accepted Answer

A) 0.018 N⋅m 
B) 2.8 N⋅m 
C) 0.028 N⋅m 
D) 0.014 N⋅m 
E) 57 N⋅m 
A) 0.018 N⋅m 
B) 2.8 N⋅m 
C) 0.028 N⋅m 
D) 0.014 N⋅m 
E) 57 N⋅m

Question 5

Different units can be used to measure the same physical quantity,differing only by some multiplicative factor.The cgs unit for magnetic field,the gauss,is equal to ________ tesla.

Accepted Answer

A) 104 
B) 10-4 
C) 0.5 
D) These units do not measure the same physical quantity. 
A) 104 
B) 10-4 
C) 0.5 
D) These units do not measure the same physical quantity.

Question 6

An electron is moving at a speed of 4.8 × 106 m/s at an angle of 30.0° with respect to a uniform magnetic field of 9.2 × 10-4 T.What is the radius of the resulting helical path? (me = 9.11 × 10-31 kg,qe = 1.60 × 10-19 C)

Accepted Answer

A) 2.6 cm 
B) 3.8 cm 
C) 5.5 cm 
D) 1.5 cm 
E) 2.9 cm 
A) 2.6 cm 
B) 3.8 cm 
C) 5.5 cm 
D) 1.5 cm 
E) 2.9 cm

Question 7

The force on a charged particle created by its motion in a magnetic field is maximum at what angle between the particle velocity and field?

Accepted Answer

A) zero 
B) 180° 
C) 90° 
D) 45° 
A) zero 
B) 180° 
C) 90° 
D) 45°

Question 8

A square loop of wire has a current going around it.The magnetic field from the current on each side of the loop results in a magnetic force on the wire on the opposite side.Each resulting magnetic force on the opposite side wire

Accepted Answer

A) pushes inward on the loop. 
B) is actually zero since a current cannot push on itself. 
C) depends on whether the current is clockwise of counterclockwise. 
D) pushes outward on the loop. 
A) pushes inward on the loop. 
B) is actually zero since a current cannot push on itself. 
C) depends on whether the current is clockwise of counterclockwise. 
D) pushes outward on the loop.

Question 9

A proton is released such that it has an initial speed of 4.1 × 105 m/s from left to right across the page.A magnetic field of 0.8 T is present at an angle of 45° to the horizontal direction (or positive x axis).What is the magnitude of the force experienced by the proton? (qp = 1.6 × 10−19 C)

Accepted Answer

A) 5.9E-33 N 
B) 9.3E-33 N 
C) 3.7E-14 N 
D) 4.5E-14 N 
E) ​3.7E-14 N 
A) 5.9E-33 N 
B) 9.3E-33 N 
C) 3.7E-14 N 
D) 4.5E-14 N 
E) ​3.7E-14 N

Question 10

Two parallel conductors are carrying currents in the same direction.The currents are non-zero and not necessarily equal.The magnitude of the magnetic field midway between them is 40 μT.If one of the currents then has its direction reversed,what is the resulting magnitude of the magnetic field midway between them?

Accepted Answer

A) a value greater than 40 μT 
B) 40 μT 
C) a value less than 40 μT 
D) It could be any value. 
A) a value greater than 40 μT 
B) 40 μT 
C) a value less than 40 μT 
D) It could be any value.

Question 11

The magnetic field of the Earth at a particular location is directed vertically downward with magnitude of 40.0 μT.An electron is moving horizontally toward the west in this field with a speed of 5.2 × 106 m/s.What are the direction and magnitude of the magnetic force the field exerts on the electron? (e = 1.6 × 10-19 C)

Accepted Answer

A) 3.33E-17,south 
B) 3.33E-17,north 
C) 2.08E-20,south 
D) 2.08E-20,north 
A) 3.33E-17,south 
B) 3.33E-17,north 
C) 2.08E-20,south 
D) 2.08E-20,north

Question 12

A 10.0-m-long copper wire with cross-sectional area 1.25 × 10-4 m2 is bent into a square loop,and then connected to a 0.25-V battery.The loop is then placed in a uniform magnetic field of magnitude 0.19 T.What is the maximum torque that can act on this loop? The resistivity of copper is 1.70 × 10-8 Ω·m.

Accepted Answer

A) 2.2E+2 N·m 
B) 1.8E+2 N·m 
C) 9.7E+2 N·m 
D) 5.6E+2 N·m 
A) 2.2E+2 N·m 
B) 1.8E+2 N·m 
C) 9.7E+2 N·m 
D) 5.6E+2 N·m

Question 13

Which statement regarding the force of a magnetic field on a current-carrying wire is true?​

Accepted Answer

A) ​The magnetic force on the wire is independent of the direction of the current. 
B) ​The force on the wire is directed parallel to both the wire and the magnetic field. 
C) ​The force takes its largest value when the magnetic field is parallel to the wire. 
D) ​All of the above statements are false. 
A) ​The magnetic force on the wire is independent of the direction of the current. 
B) ​The force on the wire is directed parallel to both the wire and the magnetic field. 
C) ​The force takes its largest value when the magnetic field is parallel to the wire. 
D) ​All of the above statements are false.

Question 14

A proton,which moves perpendicular to a magnetic field of 1.4 T in a circular path of radius 0.074 m,has what speed? (qp = 1.60 × 10−19 C and mp = 1.67 × 10−27 kg)

Accepted Answer

A) 7.3E+5 m/s 
B) 2.8E+7 m/s 
C) 5.1E+6 m/s 
D) 9.9E+6 m/s 
E) 3.9E+6 m/s 
A) 7.3E+5 m/s 
B) 2.8E+7 m/s 
C) 5.1E+6 m/s 
D) 9.9E+6 m/s 
E) 3.9E+6 m/s

Question 15

Geophysicists today generally attribute the existence of the Earth's magnetic field to which of the following?

Accepted Answer

A) convection currents within the liquid interior 
B) iron ore deposits in the crust 
C) nickel-iron deposits in the crust 
D) solar flares 
A) convection currents within the liquid interior 
B) iron ore deposits in the crust 
C) nickel-iron deposits in the crust 
D) solar flares

Question 16

A beam of electrons is sent in the positive x-direction in a region with a uniform magnetic field B in the positive y-direction and a uniform electric field E in the positive z-direction.At which of the following speeds would the electrons be deflected in the positive z-direction?

Accepted Answer

A) v  E/B 
D) There is no speed for which this will happen. 
A) v  E/B 
D) There is no speed for which this will happen.

Question 17

The term magnetic declination refers to which of the following?

Accepted Answer

A) angle between Earth's magnetic field and Earth's surface 
B) Earth's magnetic field strength at the equator 
C) tendency for Earth's field to reverse itself 
D) angle between directions to true north and magnetic north 
A) angle between Earth's magnetic field and Earth's surface 
B) Earth's magnetic field strength at the equator 
C) tendency for Earth's field to reverse itself 
D) angle between directions to true north and magnetic north

Question 18

Niobium metal becomes a superconductor (with electrical resistance equal to zero)when cooled below 9.00 K.If superconductivity is destroyed when the surface magnetic field exceeds 0.100 T,determine the maximum current a 5.31-mm-diameter niobium wire can carry and remain superconducting.(µ0 = 4π × 10−7 T⋅m/A)

Accepted Answer

A) 2660 A 
B) 423 A 
C) 211 A 
D) 1330 A 
E) 4170 A 
A) 2660 A 
B) 423 A 
C) 211 A 
D) 1330 A 
E) 4170 A

Question 19

A horizontal wire of length 3.0 m carries a current of 6.0 A and is oriented so that the current direction is 50° S of W.The Earth's magnetic field is due north at this point and has a strength of 0.14 × 10−4 T.What is the direction of the force on the wire?

Accepted Answer

A) out of the Earth's surface 
B) toward the Earth's surface 
C) due east 
D) 40° S of E 
A) out of the Earth's surface 
B) toward the Earth's surface 
C) due east 
D) 40° S of E

Question 20

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

Accepted Answer

A) its speed is greater. 
B) its mass is greater. 
C) its charge is greater. 
D) the magnetic field is weaker. 
A) its speed is greater. 
B) its mass is greater. 
C) its charge is greater. 
D) the magnetic field is weaker.

Exam 19: Magnetism

The right-hand rule allows one to find a property of the interaction of a magnetic field with a charged particle.The right-hand rule applied to moving charges:

A proton and a deuteron are moving with equal velocities perpendicular to a uniform magnetic field.A deuteron has the same charge as the proton but has twice its mass.The ratio of the acceleration of the proton to that of the deuteron is:

Different units can be used to measure the same physical quantity,differing only by some multiplicative factor.The cgs unit for magnetic field,the gauss,is equal to ________ tesla.

An electron is moving at a speed of 4.8 × 106 m/s at an angle of 30.0° with respect to a uniform magnetic field of 9.2 × 10-4 T.What is the radius of the resulting helical path? (me = 9.11 × 10-31 kg,qe = 1.60 × 10-19 C)

The force on a charged particle created by its motion in a magnetic field is maximum at what angle between the particle velocity and field?

A square loop of wire has a current going around it.The magnetic field from the current on each side of the loop results in a magnetic force on the wire on the opposite side.Each resulting magnetic force on the opposite side wire

A proton is released such that it has an initial speed of 4.1 × 105 m/s from left to right across the page.A magnetic field of 0.8 T is present at an angle of 45° to the horizontal direction (or positive x axis).What is the magnitude of the force experienced by the proton? (qp = 1.6 × 10−19 C)

Which statement regarding the force of a magnetic field on a current-carrying wire is true?​

A proton,which moves perpendicular to a magnetic field of 1.4 T in a circular path of radius 0.074 m,has what speed? (qp = 1.60 × 10−19 C and mp = 1.67 × 10−27 kg)

Geophysicists today generally attribute the existence of the Earth's magnetic field to which of the following?

A beam of electrons is sent in the positive x-direction in a region with a uniform magnetic field B in the positive y-direction and a uniform electric field E in the positive z-direction.At which of the following speeds would the electrons be deflected in the positive z-direction?

The term magnetic declination refers to which of the following?

A horizontal wire of length 3.0 m carries a current of 6.0 A and is oriented so that the current direction is 50° S of W.The Earth's magnetic field is due north at this point and has a strength of 0.14 × 10−4 T.What is the direction of the force on the wire?

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

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An electron is moving at a speed of 4.8 × 10⁶ m/s at an angle of 30.0° with respect to a uniform magnetic field of 9.2 × 10^-4 T.What is the radius of the resulting helical path? (m_e = 9.11 × 10^-31 kg,q_e = 1.60 × 10^-19 C)

Which statement regarding the force of a magnetic field on a current-carrying wire is true?

A proton,which moves perpendicular to a magnetic field of 1.4 T in a circular path of radius 0.074 m,has what speed? (q_p = 1.60 × 10−¹⁹ C and m_p = 1.67 × 10−²⁷ kg)

A horizontal wire of length 3.0 m carries a current of 6.0 A and is oriented so that the current direction is 50° S of W.The Earth's magnetic field is due north at this point and has a strength of 0.14 × 10−⁴ T.What is the direction of the force on the wire?