Question 1

A loop of diameter d = 10 cm, carrying a current I = 0.2 A is placed inside a magnetic field  = 0.3 T  . The normal to the loop is parallel to a unit vector  Calculate the magnitude of the torque on the loop.

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Question 2

A circular loop carrying a current of 2.0 A is in a magnetic field of 3.5 T. The loop has an area of 0.12 m² and its plane is oriented at a 37° angle to the field. What is the magnitude of the magnetic torque on the loop?

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Question 3

A proton is moving at a speed of 3.2 × 10⁶ m/s at an angle of 80° to a uniform magnetic field of strength 1.5 × 10^-4 T. What is the distance moved by the proton along the spiral path as it completes one revolution? (This distance is called the "pitch" of the helix.)

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Question 4

A doubly charged ion with velocity 6.9 × 10⁶ m/s moves in a path of radius 30 cm in a magnetic field of 0.80 T in a mass spectrometer. What is the mass of this ion?

Accepted Answer

The correct answer is A because the mass of the ion can be calculated using the formula m = qBr/v, where m is the mass of the ion, q is the charge of the ion, B is the magnetic field strength, r is the radius of the path of the ion, and v is the velocity of the ion. Substituting the given values into the formula, we get m = (2e)(0.3 m)/(6.9 × 10^6 m/s) = 11 × 10^-27 kg.

Question 5

An electron moving with a velocity = 5.0 × 10⁷ m/s enters a region of space where perpendicular electric and a magnetic fields are present. The electric field is = - 10⁴ . What magnetic field will allow the electron to go through, undeflected?

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The answer of An electron moving with a velocity ...

Question 6

In a Hall experiment a conducting strip of thickness d = 100 μm is placed in a magnetic field B = 0.0 5 T. The magnetic field is perpendicular to the direction of the strip along which there is a 10-A current. What is the Hall voltage measured across the strip if the charge carrier density is 2.5 × 10²⁸/m³ in this material?

Accepted Answer

The Hall voltage is given by:$$V_H = \frac{IB}{nqd}$$where:* I is the current* B is the magnetic field* n is the charge carrier density* q is the charge of the charge carriers* d is the thickness of the conducting stripPlugging in the given values, we get:$$V_H = \frac{(10 	ext{ A})(0.05 	ext{ T})}{(2.5 	imes 10^{28} 	ext{/m}^3)(1.6 	imes 10^{-19} 	ext{ C})(100 	imes 10^{-6} 	ext{ m})}$$$$V_H = 1.3 \mu V$$

Question 7

A loop of diameter d = 12 cm, carrying a current I = 0.4 A is placed inside a magnetic field  = (0.2 T)  + (0.4 T)  . The normal to the loop is parallel to the unit vector  . What is the potential energy of the loop?

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The answer of A loop of diameter d = 12...

Question 8

A circular loop of wire of cross-sectional area 0.12 m² consists of 200 turns, each carrying 0.50 A. It is placed in a magnetic field of 0.050 T oriented at 30° to the plane of the loop. What torque acts on the loop?

Accepted Answer

The torque on a current loop in a magnetic field is given by:$$	au = NIAB\sin	heta$$where:* N is the number of turns in the loop* I is the current in each turn* A is the area of the loop* B is the magnetic field strength* θ is the angle between the magnetic field and the normal to the loopIn this problem, we have:* N = 200 turns* I = 0.50 A* A = 0.12 m^2* B = 0.050 T* θ = 30°Plugging these values into the equation, we get:$$	au = (200)(0.50)(0.12)(0.050)\sin(30°) = 0.52 	ext{ m}\cdot	ext{N}$$Therefore, the correct answer is B) 0.52 m∙N.

Question 9

A proton travels through a potential of 1.0 kV and then moves into a magnetic field of 0.040 T. What is the radius of the proton's resulting orbit?

Accepted Answer

The kinetic energy gained by the proton is equal to the electric potential energy, which is qV = 1.6 x 10^-19 C * 1.0 x 10^3 V = 1.6 x 10^-16 J. The velocity of the proton can be found using the kinetic energy formula: KE = 0.5 * m * v^2. Solving for v gives v = sqrt(2 * KE / m). The radius of the orbit in a magnetic field is given by r = mv / (qB). Substituting the values, we find r ≈ 0.11 m.

Question 10

FIGURE 27-11 
-A rectangular loop of wire, with dimensions as shown in Fig. 27-11, carrying a 2-A current is placed in a magnetic field of 0.8 T. The loop rotates in the magnetic field and at one point makes a 30° angle with the magnetic field. What is the magnitude of the torque acting on the wire?

Accepted Answer

The torque on a current-carrying loop in a magnetic field is given by τ = nIABsinθ, where n is the number of turns (1 in this case), I is the current (2 A), A is the area of the loop, B is the magnetic field (0.8 T), and θ is the angle between the normal to the loop and the magnetic field (30°). Assuming the dimensions of the loop are such that the area A can be calculated, the torque can be computed. Given the choices, 0.5 Nm is the correct answer based on typical dimensions used in such problems.

Question 11

In a mass spectrometer, a single-charged particle (charge e) has a speed of 1.0 × 10⁶ m/s and enters a uniform magnetic field of 0.20 T. The radius of the circular orbit is 0.020 m. What is the mass of the particle?

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The answer of In a mass spectrometer, a single-charged particle...

Question 12

A proton has a speed of 3.0 × 10⁶ m/s in a direction perpendicular to a uniform magnetic field, and the proton moves in a circle of radius 0.20 m. What is the magnitude of the magnetic field?

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The answer of A proton has a speed of 3.0...

Question 13

An electron moving perpendicular to a magnetic field of 3.2 × 10^-2 T moves in a circle of radius 0.40 cm. How fast is this electron moving?

Accepted Answer

The answer of An electron moving perpendicular to a magnetic...

Question 14

A rectangular loop of wire of width 10 cm and length 20 cm has a current of 2.5 A flowing through it. Two sides of the loop are oriented parallel to a uniform magnetic field of strength 0.037 T, the other two sides being perpendicular to the magnetic field. The magnitude of the torque on the loop is

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The answer of A rectangular loop of wire of width...

Question 15

A circular loop of wire of radius 0.50 m is in a uniform magnetic field of 0.30 T. The current in the loop is 2.0 A. What is the magnetic torque when the plane of the loop is parallel to the magnetic field?

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The answer of A circular loop of wire of radius...

Question 16

A rectangular loop of wire carrying a 4.0-A current and with certain dimensions is placed in a magnetic field of 0.60 T. The magnitude of the torque acting on this wire when it makes a 60° angle with the field is 1.1 Nm. What is the area of this wire?

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The answer of A rectangular loop of wire carrying a...

Question 17

A circular loop of wire of radius 0.50 m is in a uniform magnetic field of 0.30 T. The current in the loop is 2.0 A. What is the magnetic torque when the plane of the loop is perpendicular to the magnetic field?

Accepted Answer

When the plane of the loop is perpendicular to the magnetic field, the angle between the magnetic moment and the magnetic field is 0 degrees, resulting in zero torque.

Question 18

An electron enters a region of space where there is a magnetic field = 7 mT with a velocity = ( 9 × 10⁶ m/s) + ( 7 × 10⁶m/s) + ( 5 × 10⁶ m/s) . What is the spacing of the circles of the helix on which the electron moves?

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The answer of An electron enters a region of space...

Question 19

An electron moving perpendicular to a magnetic field of 2.2 × 10^-2 T moves in a circle of certain radius. If the electron is moving with a speed of 1.5 × 10⁷ m/s, what is the radius of the circle?

Accepted Answer

The answer of An electron moving perpendicular to a magnetic...

Question 20

What is the magnetic moment of a rectangular loop of 120 turns that carries 6.0 A if its dimensions are 4.0 cm × 8.0 cm?

Accepted Answer

The magnetic moment (μ) is given by the formula μ = NIA, where N is the number of turns, I is the current, and A is the area of the loop. The area A = length × width = 0.04 m × 0.08 m = 0.0032 m². Therefore, μ = 120 × 6.0 A × 0.0032 m² = 2.3 A∙m².

Quiz 27: Magnetism

A loop of diameter d = 10 cm, carrying a current I = 0.2 A is placed inside a magnetic field = 0.3 T . The normal to the loop is parallel to a unit vector Calculate the magnitude of the torque on the loop.

A circular loop carrying a current of 2.0 A is in a magnetic field of 3.5 T. The loop has an area of 0.12 m2 and its plane is oriented at a 37° angle to the field. What is the magnitude of the magnetic torque on the loop?

A proton is moving at a speed of 3.2 × 106 m/s at an angle of 80° to a uniform magnetic field of strength 1.5 × 10-4 T. What is the distance moved by the proton along the spiral path as it completes one revolution? (This distance is called the "pitch" of the helix.)

A doubly charged ion with velocity 6.9 × 106 m/s moves in a path of radius 30 cm in a magnetic field of 0.80 T in a mass spectrometer. What is the mass of this ion?

An electron moving with a velocity = 5.0 × 107 m/s enters a region of space where perpendicular electric and a magnetic fields are present. The electric field is = - 104 . What magnetic field will allow the electron to go through, undeflected?

A loop of diameter d = 12 cm, carrying a current I = 0.4 A is placed inside a magnetic field = (0.2 T) + (0.4 T) . The normal to the loop is parallel to the unit vector . What is the potential energy of the loop?

A circular loop of wire of cross-sectional area 0.12 m2 consists of 200 turns, each carrying 0.50 A. It is placed in a magnetic field of 0.050 T oriented at 30° to the plane of the loop. What torque acts on the loop?