where
$I$ is the current,
$l$ is the length of a straight conductor in a uniform magnetic field
$B$ , and
$\theta $ is the angle between
$I$ and
$B$ . The force follows RHR-1 with the thumb in the direction of
$I$ .
Conceptual questions
Draw a sketch of the situation in
[link] showing the direction of electrons carrying the current, and use RHR-1 to verify the direction of the force on the wire.
Verify that the direction of the force in an MHD drive, such as that in
[link] , does not depend on the sign of the charges carrying the current across the fluid.
Why would a magnetohydrodynamic drive work better in ocean water than in fresh water? Also, why would superconducting magnets be desirable?
Which is more likely to interfere with compass readings, AC current in your refrigerator or DC current when you start your car? Explain.
Problems&Exercises
What is the direction of the magnetic force on the current in each of the six cases in
[link] ?
(a) west (left)
(b) into page
(c) north (up)
(d) no force
(e) east (right)
(f) south (down)
What is the direction of a current that experiences the magnetic force shown in each of the three cases in
[link] , assuming the current runs perpendicular to
$B$ ?
What is the direction of the magnetic field that produces the magnetic force shown on the currents in each of the three cases in
[link] , assuming
$\mathbf{\text{B}}$ is perpendicular to
$\mathbf{\text{I}}$ ?
(a) into page
(b) west (left)
(c) out of page
(a) What is the force per meter on a lightning bolt at the equator that carries 20,000 A perpendicular to the Earth’s
$3\text{.}\text{00}\times {\text{10}}^{-5}\text{-T}$ field? (b) What is the direction of the force if the current is straight up and the Earth’s field direction is due north, parallel to the ground?
(a) A DC power line for a light-rail system carries 1000 A at an angle of
$\text{30.0\xba}$ to the Earth’s
$\text{5.00}\times {\text{10}}^{-5}\phantom{\rule{0.25em}{0ex}}\text{-T}$ field. What is the force on a 100-m section of this line? (b) Discuss practical concerns this presents, if any.
(a) 2.50 N
(b) This is about half a pound of force per 100 m of wire, which is much less than the weight of the wire itself. Therefore, it does not cause any special concerns.
What force is exerted on the water in an MHD drive utilizing a 25.0-cm-diameter tube, if 100-A current is passed across the tube that is perpendicular to a 2.00-T magnetic field? (The relatively small size of this force indicates the need for very large currents and magnetic fields to make practical MHD drives.)
A wire carrying a 30.0-A current passes between the poles of a strong magnet that is perpendicular to its field and experiences a 2.16-N force on the 4.00 cm of wire in the field. What is the average field strength?
1.80 T
(a) A 0.750-m-long section of cable carrying current to a car starter motor makes an angle of
$\text{60\xba}$ with the Earth’s
$5\text{.}\text{50}\times {\text{10}}^{-5}\phantom{\rule{0.25em}{0ex}}\text{T}$ field. What is the current when the wire experiences a force of
$\text{7.00}\times {\text{10}}^{-3}\phantom{\rule{0.25em}{0ex}}\mathrm{N}$ ? (b) If you run the wire between the poles of a strong horseshoe magnet, subjecting 5.00 cm of it to a 1.75-T field, what force is exerted on this segment of wire?
(a) What is the angle between a wire carrying an 8.00-A current and the 1.20-T field it is in if 50.0 cm of the wire experiences a magnetic force of 2.40 N? (b) What is the force on the wire if it is rotated to make an angle of
$\text{90\xba}$ with the field?
(a)
$\text{30\xba}$
(b) 4.80 N
The force on the rectangular loop of wire in the magnetic field in
[link] can be used to measure field strength. The field is uniform, and the plane of the loop is perpendicular to the field. (a) What is the direction of the magnetic force on the loop? Justify the claim that the forces on the sides of the loop are equal and opposite, independent of how much of the loop is in the field and do not affect the net force on the loop. (b) If a current of 5.00 A is used, what is the force per tesla on the 20.0-cm-wide loop?
Questions & Answers
show that the set of all natural number form semi group under the composition of addition
The denominator of a certain fraction is 9 more than the numerator. If 6 is added to both terms of the
fraction, the value of the fraction becomes 2/3. Find the original fraction.
2. The sum of the least and greatest of 3 consecutive integers is 60. What are the valu
Q2
x+(x+2)+(x+4)=60
3x+6=60
3x+6-6=60-6
3x=54
3x/3=54/3
x=18
:. The numbers are 18,20 and 22
Naagmenkoma
Mark and Don are planning to sell each of their marble collections at a garage sale. If Don has 1 more than 3 times the number of marbles Mark has, how many does each boy have to sell if the total number of marbles is 113?
Solve for the first variable in one of the equations, then substitute the result into the other equation.
Point For:
(6111,4111,−411)(6111,4111,-411)
Equation Form:
x=6111,y=4111,z=−411x=6111,y=4111,z=-411
A soccer field is a rectangle 130 meters wide and 110 meters long. The coach asks players to run from one corner to the other corner diagonally across. What is that distance, to the nearest tenths place.
Jeannette has $5 and $10 bills in her wallet. The number of fives is three more than six times the number of tens. Let t represent the number of tens. Write an expression for the number of fives.
why surface tension is zero at critical temperature
Shanjida
I think if critical temperature denote high temperature then a liquid stats boils that time the water stats to evaporate so some moles of h2o to up and due to high temp the bonding break they have low density so it can be a reason
s.
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
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Source:
OpenStax, College physics (engineering physics 2, tuas). OpenStax CNX. May 08, 2014 Download for free at http://legacy.cnx.org/content/col11649/1.2
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