### Determine the magnitude of the force between

Problem 28.3

Part A

Determine the magnitude of the force between two parallel wires 27 long and 3.5 apart, each carrying 40 in the same direction

Part B

Determine the direction of the force between two parallel wires 27 long and 3.5 apart, each carrying 40 in the same direction.

attractive

repulsive

Solution :

### A long horizontal wire carries

Problem 28.9

A long horizontal wire carries 21.0 of current due north

Part A

What is the net magnetic field 20.0 due west of the wire if the Earth's field there points downward, 44 below the horizontal, and has magnitude 5*10^-5T

Solution :

### A 40.0 -long solenoid 1.35 in diameter

Problem 28.25

A 40.0 -long solenoid 1.35 in diameter is to produce a field of 0.405 at its center

Part A

How much current should the solenoid carry if it has 790 turns of wire?

Solution :

### An iron atom has a magnetic dipole

Problem 28.47

An iron atom has a magnetic dipole moment of about .

Determine the dipole moment of an iron bar 9.6 long, 1.1 wide, and 2.0 thick, if it is 100 percent saturated.

What torque would be exerted on this bar when placed in a 0.80- field acting at right angles to the bar

Solution :

### An iron-core solenoid is

Problem 28.50

An iron-core solenoid is 35 long and 1.5 in diameter, and has 750 turns of wire. The magnetic field inside the solenoid is 1.8 when 56 flows in the wire.

Part A

What is the permeability at this high field strength

Solution :

### A 550-turn solenoid is 12 long

Problem 28.69

A 550-turn solenoid is 12 long. The current into it is 37 . A 3.1 -long straight wire cuts through the center of the solenoid, along a diameter. This wire carries a 27 current downward (and is connected by other wires that don't concern us

Part A

What is the force on this wire assuming the solenoid's field points due east

Part B

to the east

to the west

to the south

to the north

Solution :

### Find at the center of the

Problem 28.72

Part A

Find at the center of the 4.9--radius semicircle in the figure . The straight wires extend a great distance outward to the left and carry a current

Solution :

### An alpha particle

Exercise 28.4

An alpha particle (charge and an electron move in opposite directions from the same point, each with the speed of 2.50×105 (the figure ).

Part A

Find the magnitude of the total magnetic field these charges produce at point , which is 1.85 from each of them

Find the direction of this magnetic field

Solution :

### A square wire loop

A square wire loop 11.0 on each side carries a clockwise current of 14.0 .

Part A

Find the magnitude of the magnetic field at its center due to the four 1.10 wire segments at the midpoint of each side.

Part B

Find the direction of this magnetic field

### Two long, parallel transmission lines

Exercise 28.22

Two long, parallel transmission lines, 40.0 apart, carry 28.0- and 74.0- currents.

Part A

Find all locations where the net magnetic field of the two wires is zero if these currents are in the same direction.

Part B

Find all locations where the net magnetic field of the two wires is zero if these currents are in the opposite direction

Solution :

### Three parallel wires each carry

Exercise 28.28

Three parallel wires each carry current in the directions shown in the figure. The separation between adjacent wires is .

Part A

Calculate the magnitude of the net magnetic force per unit length on the top wire.

Part C

Calculate the magnitude of the net magnetic force per unit length on the middle wire

Part E

Calculate the magnitude of the net magnetic force per unit length on the bottom wire

Solution :

### Calculate the magnitude of

Exercise 28.30

Part A

Calculate the magnitude of the magnetic field at point P due to the current in the semicircular section of wire shown in the figure

Part B

Find the direction of the magnetic field at point P

Solution :

### A closely wound, circular coil with radius

Exercise 28.32

A closely wound, circular coil with radius 2.10 has 850 turns.

Part A

What must the current in the coil be if the magnetic field at the center of the coil is 5.50×10−2 ?

Part B

At what distance from the center of the coil, on the axis of the coil, is the magnetic field half its value at the center?

Solution :

### A closed curve encircles several conductors

Exercise 28.35

A closed curve encircles several conductors. The line integral around this curve is 3.64×10−4 .

Part A

What is the net current in the conductors?

B

If you were to integrate around the curve in the opposite direction, what would be the value of the line integral ?

Solution :

### A solenoid is designed to produce a

Exercise 28.41

A solenoid is designed to produce a magnetic field of 3.10×10−2 at its center. It has a radius of 1.00 and a length of 46.0 , and the wire can carry a maximum current of 12.0 .

Part A

What minimum number of turns per unit length must the solenoid have?

Part B

What total length of wire is required?

Solution :

### A long, straight wire carries a current of

Problem 28.52

A long, straight wire carries a current of 2.50 . An electron is traveling in the vicinity of the wire.

Part A

At the instant when the electron is 4.40 from the wire and traveling with a speed of 6.20×104 directly toward the wire, what is the magnitude of the force that the magnetic field of the current exerts on the electron?

Part B

What is the direction (relative to the direction of the current) of this force?

Solution :

### Two identical circular, wire loops

Problem 28.55

Two identical circular, wire loops 44.0 in diameter each carry a current of 2.50 in the same direction. These loops are parallel to each other and are 22.0 apart. Line ab is normal to the plane of the loops and passes through their centers. A proton is fired at 2850 perpendicular to line ab from a point midway between the centers of the loops.Find the magnitude of the magnetic force these loops

Solution :

### Two long thin parallel wires

28.7

Two long thin parallel wires 13.0 apart carry 35 currents in the same direction

Part A

Determine the magnetic field vector at a point 10.0 from one wire and 6.0 from the other (see the figure

Part B

Express your answer using two significant figures

Solution :

### Two long parallel wires

28.22

Two long parallel wires 8.20 apart carry 16.5- currents in the same direction

Part A

Determine the magnetic field vector at a point P, 12.0 from one wire and 13.0 from the other. See the figure

Part B

Assume that positive x axis is parallel to the shortest side of the triangle and points to the right

Solution :

### A 2.2 -diameter copper wire

28.27

A 2.2 -diameter copper wire carries a 39 current (uniform across its cross section).

Part A

Determine the magnetic field at the surface of the wire

Part B

Determine the magnetic field inside the wire, 0.50 below the surface

Part C

Determine the magnetic field outside the wire 2.5 from the surface.

Solution :

### Three long parallel wires are

28.52

Part A

Three long parallel wires are 3.5 cm from one another. (Looking along them, they are at three corners of an equilateral triangle.) The current in each wire is 8.00 A, but its direction in wire M is opposite to that in wires N and P (See the figure ). Determine the magnitude of the magnetic field midway between points and .

Part B

Determine the direction of the magnetic field

Solution :

### A solid conductor with radius is supported

Exercise 28.32: Coaxial Cable

A solid conductor with radius is supported by insulating disks on the axis of a conducting tube with inner radius and outer radius (see the figure ). The central conductor and tube carry equal currents in opposite directions. The currents are distributed uniformly over the cross sections of each conductor.

Part A

Derive an expression for the magnitude of the magnetic field at points outside the central, solid conductor, but inside the tube

Part B

Derive an expression for the magnitude of the magnetic field at points outside the tube

Solution :

### An electron enters a uniform magnetic

An electron enters a uniform magnetic field * B* = 0.33 T at a 35° angle to

*. Determine the radius*

**B***r*and pitch

*p*(distance between loops) of the electron's helical path if its speed is 2.0 10

^{6}m/s. See Fig. 27-42.

Solution :

### Two long wires are oriented so that

Two long wires are oriented so that they are perpendicular to each other. At their closest, they are 20 cm apart. What is the magnitude of the magnetic field at a point midway between them if the top one carries a current of 20 A and the bottom one carries 5 A?

Solution :

### If an electric wire is allowed to produce a

28.2

If an electric wire is allowed to produce a magnetic field no

larger than that of the Earth (.50*10^-4) at a distance of 19 cm from the wire, what is the maximum current the wire can carry?

I(max) = ??

Solution :

### In the figure the top wire is

28.53

In the figure the top wire is 1.20 -diameter copper wire and is suspended in air due to the two magnetic forces from the bottom two wires. The current is 46.0 in each of the two bottom wires

Calculate the required current flow in the suspended wire.

I=?

Solution :

### A square loop of wire

### A straight stream of protons

Problem 28.10

A straight stream of protons passes a given point in space at a rate of 2.7×109 .

What magnetic field do they produce 1.1 from the beam?

Solution :

### Two straight parallel wires are separated

Problem 28.12

Two straight parallel wires are separated by 6.1 . There is a 2.3 current flowing in the first wire.

Part A

If the magnetic field strength is found to be zero between the two wires at a distance of 2.3 from the first wire, what is the magnitude of the current in the second wire?

Part B

What is the direction of the current in the second wire?

currents flow at the same direction

Solution :

### An electron enters a large solenoid

Problem 28.54

An electron enters a large solenoid at a 7.4 angle to the axis.

Part A

If the field is a uniform 3.1×10−2 , determine the radius of the electron's helical path if its speed is 1.9×107 .

Part B

Determine the pitch (distance between loops) of the electron's helical path.

Solution :

http://answers.yahoo.com/question/index?qid=20070424120455AAP9y6I

### A square loop of wire, of side , carries a current

28.46

a square loop of wire , side d carries a vurrent i (a) determine the magnatic field B at points on a line perpendicular to the plane of the square ............

Solution :

### A triangular loop of side

(III) A triangular loop of side length a carries a current I. If this loop is placed a distance d away from a very long straight wire carrying a current I^{'} (read: I prime), determine the force on the loop.

Solution :

Solution :

اضغط هنا

### A 40 cm-long solenoid, 1.8{\rm cm} in diameter,

A 40 -long solenoid, 1.8 in diameter, is to produce a 0.50 magnetic field at its center.

If the maximum current is 4.7 , how many turns must the solenoid have?

B=μ

_{o}*N/L*I

L=0.4 m

I=4.7 A

B=0.5 T

=>Number of turns N

**=33863 turns**

### A rectangular loop of wire

A rectangular loop of wire is placed next to a straight wire, as shown in the figure . There is a current of 3.5 in both wires.Determine the magnitude of the net force on the loop.Determine the direction of the net force on the loop

Solution :

### You want to get an idea of the magnitude

You want to get an idea of the magnitude of magnetic fields produced by overhead power lines. You estimate that a transmission wire is about 15 above the ground. The local power company tells you that the line operates at 10 and provide a maximum of 11 to the local area

Sol :

### The same amount of current

The same amount of current is flowing through two wires, labeled 1 and 2in the figure, in the directions indicated by the arrows. In thisproblem you will determine the direction of the net magnetic field at each of theindicated points (A - C)

Sol :

### A wire, in a plane, has

Figure 28-37.

A wire, in a plane, has the shape shown in Fig. 28-37, two arcs ofa circle connected by radial lengths of wire. Determine**B** at point C if *R*_{1} = 10 cm,*R*_{2}= 15 cm, = 36°, and the current *I* = 2.0 A.

Sol :

B

_{c}= μ

_{o}.I/2.R

_{o}.I/2.)(1/R

_{1}-1/R

_{2})x 0.1

^{-7}x2.0)(1/0.1 - 1/0.15)x0.1 =41.9x10

^{-8}T

^{-7}T

ضع اسئلتك كتعليق وسيتم الاجابة باسرع وقت ممكن

A square loop of wire, of side , carries a current

Determine the magnetic field at points on a line perpendicular to the plane of the square which passes through the center of the square (see the figure ). Express as a function of , the distance along the line from the center of the square

Solution :

اضغط هنا