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The Right Hand Rule.

Case study : the right hand rule

Use the Right Hand Rule to draw in the directions of the magnetic fields for the following conductorswith the currents flowing in the directions shown by the arrows. The first problem has been completed for you.

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Experiment : magnetic field around a current carrying conductor

Apparatus:

  1. one 9V battery with holder
  2. two hookup wires with alligator clips
  3. compass
  4. stop watch

Method:

  1. Connect your wires to the battery leaving one end of each wire unconnected so that the circuit is not closed.
  2. One student should be in charge of limiting the current flow to 10 seconds. This is to preserve battery life as well as to prevent overheating of the wires and battery contacts.
  3. Place the compass close to the wire.
  4. Close the circuit and observe what happens to the compass.
  5. Reverse the polarity of the battery and close the circuit. Observe what happens to the compass.

Conclusions:

Use your observations to answer the following questions:

  1. Does a current flowing in a wire generate a magnetic field?
  2. Is the magnetic field present when the current is not flowing?
  3. Does the direction of the magnetic field produced by a current in a wire depend on the direction of the current flow?
  4. How does the direction of the current affect the magnetic field?

Case study : magnetic field around a loop of conductor

Consider two loops made from a conducting material, which carry currents (in opposite directions) and are placed in the planeof the page. By using the Right Hand Rule, draw what you think the magnetic field would look like at different points around each of the twoloops. Loop 1 has the current flowing in a counter-clockwise direction, while loop 2 has the current flowing in a clockwisedirection.

If you make a loop of current carrying conductor, then the direction of the magnetic field is obtained by applying the RightHand Rule to different points in the loop.

If we now add another loop with the current in the same direction, then the magnetic field around each loop can be added together to create a stronger magnetic field. A coil of many such loops is called a solenoid . The magnetic field pattern around a solenoid is similar to the magnetic field pattern around the bar magnet that you studied in Grade 10, which had a definite north and south pole.

Magnetic field around a solenoid.

Real-world applications

Electromagnets

An electromagnet is a piece of wire intended to generate a magnetic field with the passage of electric current through it.Though all current-carrying conductors produce magnetic fields, an electromagnet is usually constructed in such a way as to maximizethe strength of the magnetic field it produces for a special purpose. Electromagnets are commonly used in research,industry, medical, and consumer products. An example of a commonly used electromagnet is in security doors, e.g. on shop doors which open automatically.

As an electrically-controllable magnet, electromagnets form part of a wide variety of "electromechanical" devices: machines that produce a mechanical force or motion through electricalpower. Perhaps the most obvious example of such a machine is the electric motor which will be described in detail in Grade 12. Other examples of the use of electromagnets are electric bells, relays, loudspeakers and scrapyard cranes.

Experiment : electromagnets

Aim:

A magnetic field is created when an electric current flows through a wire. A single wire does not produce a strong magnetic field,but a wire coiled around an iron core does. We will investigate this behaviour.

Apparatus:

  1. a battery and holder
  2. a length of wire
  3. a compass
  4. a few nails

Method:

  1. If you have not done the previous experiment in this chapter do it now.
  2. Bend the wire into a series of coils before attaching it to the battery. Observe what happens to the deflection of the needle on the compass. Has the deflection of the compass grown stronger?
  3. Repeat the experiment by changing the number and size of the coils in the wire. Observe what happens to the deflection on the compass.
  4. Coil the wire around an iron nail and then attach the coil to the battery. Observe what happens to the deflection of the compass needle.

Conclusions:

  1. Does the number of coils affect the strength of the magnetic field?
  2. Does the iron nail increase or decrease the strength of the magnetic field?

Magnetic fields

  1. Give evidence for the existence of a magnetic field near a current carrying wire.
  2. Describe how you would use your right hand to determine the direction of a magnetic field around a current carrying conductor.
  3. Use the Right Hand Rule to determine the direction of the magnetic field for the following situations:
  4. Use the Right Hand Rule to find the direction of the magnetic fields at each of the points labelled A - H in the following diagrams.

Questions & Answers

What is a vector
Mercii Reply
vector is anything that has both a direction and a magnitude .they are usually drawn as pointed arrows ,the length of which represents a vector's magnitude
Tetteh
what is electronics?
Edward
how to calculate the reading on voltmeter or ammeter
mosima Reply
why is HCl considered a strong acid
Sphiwe Reply
it dissociate almost completely
Tetteh
what is metal displacement
Andile Reply
what is an electric field?
Noluthando Reply
is the charge of an electron always 1,6 ×10^-19? and the mass is always 9,1×10^-13?
Neo Reply
how to calculate a distance between charges
Celucolo Reply
juss apply the formula of the Electrostatic force
Noluthando
how to show polarity
Sandiso Reply
what can ii do to pass physics
Slindile Reply
Use previous years question papers to understand how questions are answered and asked
Joseph
but it hard ii am a slow learner
Slindile
Then the best thing to do is that immediately you are done reading through a certain topic, and you think you understood everything in that topic that's when you can use previous question papers and answer questions related to the topic. I think that's not difficult
Joseph
mm ii will try
Slindile
Good
Joseph
Here's a tip in reading textbooks, don't read it like a novel. First, flip through the pages—scan the chapter that you wanted to read. Second, go to the end of the chapter. Usually, there's a quiz at the end, so if will give you the important information that you need to know.
Sarah
Third, go to the beginning of the chapter and read through the words that were printed in bold: Titles, subtitles, headings, important words —because it helps to break down information.
Sarah
Fourth, read the first sentence of the chapter—if it is written by a good author; therefore, it will also have a good introduction. Check also the last sentence of the chapter to sum it up. Finally, read the whole chapter. You won't read it twice anymore.
Sarah
It looks hard, cause there are so much to do but read it thoroughly, it's easy and it will help you to save time and comprehend better. If you don't really have interest on reading—there are various of videos in youtube😊
Sarah
Oh, so em dashes turn into question marks :' (( nvm. Goodluck to all of us!
Sarah
How many ways can we calculate the empirical formula
Joseph Reply
How is current divided between resistors in parallel
Joseph
1/R=1/R+1/R
Slindile
tanx
Joseph
ii know 2 ways
Slindile
what's the other way
Joseph
What is the meaning of Coulomb's law
Nozipho Reply
Electronic magnetic field
Pride Reply
what is an emf ?
Nobuhle Reply
electromotive force
Tetteh
what are moments of a force
Mercy Reply
the moment of a force" is a measure of a tendency to cause a body to rotate about a specific point or axis....a moment is due to force not having equal and opposite force directly along its line of action.
Bhuboy
how to calculate the magnitude of the force of repulsion
Vicky Reply

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Source:  OpenStax, Siyavula textbooks: grade 11 physical science. OpenStax CNX. Jul 29, 2011 Download for free at http://cnx.org/content/col11241/1.2
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